i would suggest getting a piece of posterboard, cutting out a rectangle, and taping it dull side up on your desk. that should get rid of any problems with the mouse not reading properly. you might have to replace the surface every month, but it is GREAT, at least with the intellimouse explorer that i use (i like this better than my razor boomslang 2000, 3M precise surface combo).
[edit1] the color of your surface doesn't matter nearly as much as the pattern and reflectivity. i got my explorer right after they came out, so i've had a a lot of time to test surfaces. 10 sheets of notebook paper taped down real tight works great too, but it tends to bunch with humidity after about a week. as long as your surface is smooth, non-reflective and has a distinct pattern, you should be fine.
Shooters 100% right that uniformity of pattern is actually not a good thing. if the pattern repeats over and over in nearly the same pattern, the mouse gets confused. it can't tell one similar area from another. thats what is great about paper: it has a very distinct and random pattern that is easily read by the mouse. its also tres' cheap
anyone else find it funny that best buy displays the optical mice on a mirror?
[edit2] i hate the "set orientation", as i never sit quite the same way, and it bothers me. personal taste.
--jacob