I guess TS decided to resurrect this two year old topic by putting it over on the Discuss sidebar...
For me, it's the Corsair M90. By far the best gaming mouse I have used, so of course, Corsair discontinued it (and its M95 version, which is supposed to be an improvement. Unfortunately, it has a nasty firmware bug and inferior build quality, so to me it's worse than the M90) so they could replace it with another me-too MMO mouse with a veritable keyboard under the thumbrest (right handed), just like all those ones I didn't buy from every other mouse manufacturer when I first ended up with the M90. I hope they see the light and bring it back, or that someone else offers something comparable, before the ones I have break or wear out.