Relatively new with a 7D

I don't post much on the forum but I've been a long time lurker.

I've recently purchased a 7D and it seems awesome. The only problem I've got at the moment is that it doesnt want to work (autofocus) with my Sigma 70-200 - there is a thread about this. Apart from that everything is rosey.

Just wanted to say I have found many posts on here very insightful and some of the tips people have come up with have been very useful.