Hey biiv...
Here's my bit of advice - I've had two webcams. The first was Logitech. Fairly low quality. Could take pictures and video, but the picture quality was pretty bad. Cheap though.
This new one I have is a Microsoft LifeCam, which is really nice. Has all sorts of nifty settings, takes good pictures and does the video thing - you can also use it (like Logitech) with MSN to have video conversations.
I'd ask what you were using it for. If you want to use it to make videos or take pictures, get a better quality one (even though they are more expensive). If you're just looking for one to have MSN conversations with - you can get a lower quality one which is cheaper.
I don't know how much the Microsoft one I have no costs, but my Logitech one was between $60-80. (Can't remember exactly)
Also found a nifty guide online which should be useful:
http://products.howstuffworks.com/we...ying-guide.htm