Somehow, I can't see spending a fortune on a mouse. My limit is about $10 for one. After that, I feel as if I've committed some unGodly extravagance.
Lately; I have centered my attention on Mitsumi Optical scroll mice. They're between $8 and $9, all over my town, and I find the performance perfectly acceptable. Linux and Windows 2K/XP see them as generic PS/2 devices and have absolutely no problem with them. We've outfitted every box here that has a graphic interface with one and I just bought one as an add-on to the laptop.
These mice are particularly suitable for such travelling usage as an auxilliary device for a laptop gets. They're seemingly impervious to dirt, run well on any surface I've tried them on and are durable. I recommend then highly. And you can save enough in buying one to take your love out to lunch.