My all-time favorite pointing device was an optical trackball from Microsoft (I forget the model name). I haven't found one of those since the last I had one was stolen (yes, really) back in 2003ish.
The IBM Model M [1] (and certain imitators), the Das Keyboard [2], the HP Wireless Elite [3], and even the keyboards on Thinkpads [4] are among my all-time top-five favorite keyboards. The original run of Microsoft Natural keyboards [5] (back before they became bulbous "multimedia" train wrecks of UI design [6][7]) were a very distant fifth place, though.
1: http://sob.apotheon.org/?p=61
2: http://sob.apotheon.org/?p=1193
3: http://sob.apotheon.org/?p=865
4: http://media.laptoplogic.com/data/reviews/images/73/keyboard...
5: http://images.tigerdirect.com/skuimages/large/M17-1806-main....