Warranties are very important to me on major purchases.
It is a way for a manufacturer/vendor of saying we stand behind this product. I have a friend who is now on a second frame warrantied by Trek (on his third Trek bike after the original one he bought failed). And they did not try to weasel out of their "word" either. And each frame was an upgrade over the previous one. That, my friends, is SERVICE!
Would I buy solely based on warranties? NO, but if two/three/four bikes I test-ride are very possible choice-wise, I'll go with the best warrantie anyday.