I don't know if sturdy is the correct term. My RAT7 just went out, lookin into a new one for <$70 USD. I really liked how sturdy, if not just "heavy" it felt, but dont want to shell out another $100+ on a new one. I dig the Corsair ones and some of the Logitech ones, some are too small tho. Regular size is prefered. I've never been a fan of Razer tho. Also, don't really need an MMO mouse with like 10 extra buttons, tho 2-3 extras wouldn't be too bad.
I personally have been using the Logitech G series since the 500 came out, and I've aways been very pleased, especialy as far as sturdiness goes. Never had one crap out on me, if they broke it was always my fault and all of them lastet 2-3 years even im my hands.
I'm being stupid, it's not since the 500 came out, but since the first gaming mouse with that specific form and layout the G500 has came out, I just don't remember the exact number that goes with it.
I have been using a g5 from logitech for about 7-8 years now, and it is still rocking It is pretty much a standard mouse, nothing fancy or special. But the way it lays in my hand, its perfect. Now the g5 is not for sale anymore i think, but you can take a look at the new version the logitech g500. I have seen in a shop and it is practically the same.
But you might also want to go to a store and just feel a couple of them. See how they fit in your hand etc. Because it can be pretty personal.
At the store the only one that felt real good was that new G700 i think. I just dont want to spend $99 on a mouse again, especially since I only really play some fps casually, not so much wow or other mmo's anymore. the Corsair M60 looks good...