Plaidophile

Well, okay, they're still better than optomechanical ones, but they still get gunky, and they're too lightweight so even the weight and/or springienss of their own cord makes them move around too easily, and the optical sensors still get confused way too easily on too many different surface types, like the smooth black plastic of the mouse section on my keyboard tray at home (which isn't designed to accommodate any additional mousing surface), but even textured fabric mousepads still have problems since often the weave is so regular that sometimes the sensor can't really tell which direction it's going (sometimes it thinks I've moved the mouse 10 times as far in the exact opposite direction, for example).

Plus, I still miss being able to use inertia to 'whip' the cursor around. There was something very nice about being able to just rev the ball while picking the mouse up, and then putting it back down when the cursor was in a certain vicinity. That's more useful on windowing systems which support point-to-focus, though.

If it weren't for roller/ball gunk problems I'd probably still be using an optomechanical mouse, or a trackball (though as much as I loved my Logitech Marble Wheel, the current models really suck and even the old ones make my right thumb cramp too much now).

I guess of all the different technologies people have tried, pure-optical mice are the least-crappy though. Active-tablet mice (e.g. Wacom) are annoying to use (since they're still active even a cm or so away from the surface, and the direction of motion is relative to the tablet rather than to the mouse), touchpads are just plain irritating (they can be precise OR fast but not both), and I'm glad that the two-tilted-wheel mice that a few manufacturers were messing with back in the early 90s never caught on because holy cow were those crappy. (Does anyone else even remember those? I know that Digital included them with some of their DECstations, and IIRC the mice themselves were manufactured by Honeywell. The principle was that there were two discs on the bottom of the mouse, one tilted to the left and one tilted to the back, so that in theory one wheel would only respond to horizontal motion and the other would only respond to vertical, but in practice both ended up just basically doing whatever they wanted depending on the kind of surface they were on.)

Still, the mouse as we know it today hasn't had any significant change in over 10 years. That's not necessarily a bad thing, of course, except that it was still just an incremental improvement over the design from the previous 15 years, and the current ones aren't really any better than the first ones (while the optomechanical mice underwent continuous improvement over their lifetime). I guess laser mice might be even better than LED mice, but those are still something of a niche item, and it seems like they'd still have the same general problems.

Maybe the next generation mouse will be something which uses MEMS to measure acceleration and a simple proximity sensor to determine whether it's on a surface or not. Then you could easily have the exact feel of an old optomechanical mouse without any of the maintenance problems. (Though it seems I'm not the first to think of that.)