I have to agree on the Trackball Explorer (Score 1)

I have been using one for years as well, and have worn one out, and have 2 left, one on my laptop and one on my Tower, and damn wouldn't I love to have a few more. I used to use the big Kensington ones, but the Trackball explorer is so much better. More precise, less wrist discomfort (for me at least) and I love the scroll wheel placement.

Damn if I could I would buy a case of these things, so i would never be without, but they are pushing $200 on ebay now.