OK. I will refrain from discussing mad cow disease within a semi-joking context, and perhaps you can simply refrain in general.

back on topic ... the intellimouse explorer is going back tomorrow, unless i can configure a third-party driver to make it more user-friendly.

I also found the Intellimouse's middle click to be odd. I had it set up for expose - all windows, but there was a very odd, very noticeable delay when hitting it to when the windows would tile.

I also found the scroll wheel to be weird, since it has no notches, i couldn't tell when i was moving it.

I'm sticking with my trackball, so this whole thread is a moot point for me.

a trackball would be useful for some things i do, but do you think they are a bit large vs. 'normal mice' to carry around in a laptop bag?

I just bought the Mighty Mouse. I'm really enjoying it. I think the only problems I have with it are software related.

Firstly, the scrolling nub only works on the active window when your mouse is in the same window/pane that is to be scrolled. The active browser window I'm looking at doesn't scroll when my mouse is elsewhere on the screen including the title bar of this window. Because of this, when you're scrolling along in a web page and scrollable content comes along and gets placed under your cursor, page scrolling stops and the scrollable content scrolls until it's finished, after which page scrolling resumes. This is buggy for some ads in iframes when there is nothing to scroll. There doesn't seem to be a problem with this while scrolling up, but while scrolling down the page scrolling stops while the mouse driver attempts to scroll down the unscrollable ad container. I think I should be able to scroll the active window regardless of where my curser is... or at least scroll the most recently focused item, but only if the focus was attained via user interaction as opposed to script controlled focus. Is this behavior common of scroll wheels on other mice?

Secondly, it's not possible to set the scroll button to act as a left-click or a right-click. If you turn the scroll button off, then nothing happens when you use it. I think it would be convenient to keep my finger on the ball and just click as usual.

Yes. I have a Kensington trackball with a scroll ring, and a regular scroll-wheel mouse. Both of them behave that way using the standard Apple driver (I don't have the Kensington driver or the Mighty Mouse driver installed).

After all of my Apple-talk, I admit that I myself use a Logitech optical mouse, although I got it when I still used a PC, so I think I can be excused. ;)