I have the $80 mouse. Hey, it's my main point of interaction with the world.
This accessory is a must, and it's priced right at $4...
mouse feet dots at newegg
Little teflon tape circles that you put over each mouse "foot". The Logitech mouse feet are fairly slippery to begin with, but they degrade quickly because they're thin and not glued on too well. This makes the feet extra-slippery and also preserves them against the harsh world of rough surfaces and gunk. After a month you change out the dots and hey, it's like a new mouse.