I used to have a couple of logitech webcams (2 different models including a very expensive one, used on 2 different computers with 2 different OS). The cameras were great (awesome picture), but the software was cr@p for both of them. Frequent crashes requiring rebooting and other compatibily issues really turned me off.
I now have a Microsoft LifeCam and it works flawlessly with Skype. Good picture, very stable, great microphone built-in.
That's the one I have now:
That's the expensive one I used to have: