No, I already had ML running on the HDD. I copied the entire hard drive over to the SSD with Disk Utility, running on an ML installer flash disk.

I don't think old plug-ins is the problem, as they all worked fine before. I've cleared all the caches and restarted after letting Spotlight re-index, but it's left thousands of log items. I'm not sure that all meta-data has been added.
For example, all my PostScript fonts threw sandbox related mdworker log errors. (Yes, the fonts have their resource forks!)

Follow-up
 

Wow -- what a difference in boot up. For those of you working with a 17" MacBook Pro (Models A1151 A1212 A1229 and A1261), I strongly recommend these directions: MacBook Pro 17" Models A1151 A1212 A1229 and A1261 Hard Drive Replacement. Aside from the difficulty in handling so many little screws with 75-year-old fingers, I got her done.

I hope that if I make it to 75 years old, I can get her done with my fingers too.

I have been using a Seagate Hybrid drive ( 4 GB SS + 7200 rpm 500Gb spinning platter ) for 18 months or so and have been very happy with it. It was so much faster than the installed 5400rpm supplied by apple.

I finally had the wherewithal to buy a SSD and went for the 180 GB Intel 520 ( couldn't afford the 250 GB). This is an awesome drive. I've got around the storage limit by moving a whole bunch of files ( which are so seldom accessed ) onto my original Seagate drive which sits in a 800 firewire connected external case.

I can see why people say they won't return to a platter drive after moving to an SSD. It makes everything so incredibly snappy. I've finally sorted the last block in the chain, my 2011 17" MBPro now runs at its best. This is definitely the best money i have spent in a while.

Yes, everything is "much snappier" now. Lengthy lists of files and folders, which used to take a moment to display in column view (the first time) are now instant.
I've got lots of large PDFs of many pages of scanned images, which I can now browse in QuickLook without any hiatus when scrolling through.
Large apps like Creative Suite are much faster to load, and "present themselves" a bit more surely when they finish loading. Also, it's much better at handling lots of things happening at once.
Battery life seems slightly improved, too. And it's silent.

It's certainly convinced me that I'll go for the SSD option in my next iMac, if there are any.

Yeah, I'd have put an SSD in my iMac if they hadn't been so darned expensive when I bought it -- still are from Apple. Although I don't mind disassembling a MBPro, I wouldn't tackle the iMac what with suction cups to pull off the glass, etc. That's out of my league. What I'm hoping for is a Thunderbolt SSD that I can hang externally but still get great speed.

http://eshop.macsales.com/shop/Thunderbolt

I have installed a few SSDs into iMacs and it can be pretty scary for most users. I must admit i dread changing disks onsite in iMacs (had to do 6 recently....falling like flies 3.5 year old) as there is quite a bit that can go wrong although it only take 40 mins ;-) you certainly get a nervous sweat on ;-)

But in saying that a IT professional or Apple Technician should only charge £80 labour to do a drive swap tops....DeltaMac might chime in on that one.

My local Apple Dealer (not an Apple Store) won't install one of the available kits because it voids my warranty (which is still operative). But here's what Tom's Hardware says:

I've read the last part elsewhere, too. OWC has a kit for adding an SSD without taking out the HD that's there, but it's a tough DIY, so they recommend letting them do it.

Elgato has a 120GB Thunderbolt SSD for $300 (plus $60 for the cable) that's supposed to be quick.

The charge for a hard drive swap will vary depending on two main points.
The Mac model, and what needs to be done with software.
An older MacBook, with only the battery and a tiny panel in the way, takes only about 5 minutes tops.
A MacPro, maybe even less. I might not charge anything for labor on either of those, for a simple "old one out, new one in, and done (no software)", unless the customer brought in his own hard drive for us to install.
An older iBook (horrible little beasties!) I always charged for 1.5 hours of labor, even without software work. Then the little ribbon cable for the hard drive was very easy to damage, so very often there was more charge because of "collateral damage". That shop had a basic charge for data transfer for a single drive-to-drive transfer (not trying to be redundantly repetitious :D ) adding 1/2 hour labor charge. Yes, data copies take longer than that, but it's mostly just the equipment setup, then keep an eye on the process.
So - "£80 labour to do a drive swap tops..." - that sounds like a reasonable high end, when the hard drive/data is the only factor.

You left out two other points - supply and demand, and what the market will bear.

If everyone is charging $100, you're going to pay $100. If no one will pay $100, the rate will be less.

As for me - the minimum I would accept for installation in a laptop is $50 - for nothing other than swapping hard drives and ensuring the new one works (is installed properly). For an iMac - I wouldn't install that for anything less than $150, if at all.

Neither of the last two posters has mentioned an external drive, but I assume they us an external drive case to clone the internal to the external-soon-to-be-internal replacement.

One thing I haven't understood about that process is how you can be sure that the rescue partition is put on the new drive. Not knowing that, I installed Lion from a DVD I had made and then cloned the old (internal) to the new (external) and then swapped them. Glad to know that I saved myself something between $100 and $150 by doing it myself.

I didn't say those were the only criteria for service labor charges - just the main ones. What YOU may charge is usually controlled by The Boss. In my case, I am The Boss, so I charge what I choose to call a reasonable amount. That is mostly determined by my estimate of the job time, and the care that is needed for the replacement.
I give quotes before the repair commences. If the customer accepts the quote, then that's what I charge. If they don't accept the quote, then we decide on a more equitable charge (probably with fewer options on the final job), or the customer goes elsewhere.
I also expect that you have never had an old iBook apart... It's much more challenging than any iMac. I counted once - there's 50 screws to remove to get to the hard drive on a typical iBook. How many screws do you remove to get at the hard drive on an A1181 MacBook. That would be "none".
You would be fine on newer Apple laptops, and not so good on those prior to MacBooks.

I've been in and out of a lot of iMacs, from the old bondi-blue iMac, to the latest ones. There's easy - the first G5 iMac; to challenging - the iSight iMac G5, and then the white intel iMacs. The newer iMacs, which need suction cups to get at the display? not so bad... But, I'm expecting that Apple will continue with making Macs more difficult to repair - waiting for a retina display iMac to be mostly a sealed unit. $150 for repair labor on something like that? It'll probably seem cheap... :D

The first Mac I opened was an SE/30. I installed a Dayna ethernet adapter plugged into its Processor Direct Slot through a PDS adapter. It still works, though I did have to frig with it CRT settings when the image began to shrink. Since then I've upgraded or repaired a 7100/66, a Beige G3 to a G4, a B&W G3, and a PM G5 so I wasn't disturbed to open a MBP.

I was worried about this, but I ended up with a Restore partition, though I'm not sure quite how it happened. I partitioned the disk to HFS+, journaled; and then restored the original hard drive partition. (I though it was the partition, rather than the whole drive). Anyway, it all works now.

What's weird is that the Recovery partition and my USB thumb drive with Mountain Lion installer both seemed to have selected and signed into my wireless router, which has a password. There are several other wireless routers that they could have chosen nearby, including some freebies, so how did two completely unrelated disks "know" my preference -- and possibly the password?

I am also The Boss - and I charge a blend of what I think is reasonable (often less than market), market rate, and what the client is willing to pay. Generally speaking, I'm cheap.

My first one was a Mac Plus - upgrading it from 1MB to 4MB, which required clipping a couple of resisters on the motherboard - talk about an operation that makes you nervous about screwing up! I don't remember how much I charged, but it probably should have been more.

The scariest part of those Classic Macs was the CRT voltage ~1500 volts, so adjusting any of the analog stuff on the motherboard required reaching past that. Adjusting the screen size was easy, though -- just start an app with an on screen ruler and compare to an external one.