Update - had the Logitech 305 now (2 of them) for a few months - picked them both up for 59.99 on sale. Wow, for such a LOW price, these things work incredibly well. I have a pile of semi older top tier "gaming" mice that are wired, and this thing is as good or better than the best of those. Using it about 10 feet away from the dongle/port for the home theater PC mouse, and it's still exact, precise, and visibly lagless.
Great recommendation, I too would tell anyone to grab these if they need a good wireless AA batter mouse. I have them set at max performance/polling, and still haven't replace the batteries that came with them, and the HTPC unit gets used a good 8 hours a day I would wager overall.
Good times from Logitech.