I believe the OP wants a mouse with a on-the-fly DPI changer.
X5 is not a bad choice but not many can get use to the wideness of the mouse. I personally use the X5 for work.
You take a look at Logitech G500 or G9x as they have extra buttons just for changing DPI on-the-fly. G500 = palm grip. G9x = Claw grip.
Both go for cheap @ Logitech form their ever so often dented box sale.
It's a pity there no dented box sale in Singapore, I would so get them despite having alot of mices already.
P.S Undarken is my nick on a local forum.Edited by squarebox - 7/28/11 at 1:48pm