Torx is a 6 sided pattern like allen, but the sides are cupped rather than straight. It kind of makes a rounded star pattern. To my old, crummy eyes, I often have to put on my reading glasses to tell the difference. Its conceivable that you could fit a under-sized allen wrench into a torx socket and it would seem stripped. I'm not saying this is the case for you, but something to think about.

Look at this web site, it shows all sorts of fastener heads. The other one that has messed me up in the past is the posidriv - which is very similar to philips head, but can get messed up if you try to use a philips head driver.

http://www.lara.com/cgi-bin/store/commerce.cgi?cart_id=6714902.30178&detailpage= screwtypes