Anderson Silva or Georges St. Pierre?  Who is the best and why?

I'm going to go with Silva. I like GSP more but it's hard to argue with Silva's UFC record. GSP has suffered losses to Hughes and Serra, though those are his only 2 losses.

I think it's GSP. He's impressed me more lately and I feel like his fights have been more significant. It's a tough argument and both guys are obviously at the peak of the sport. I want Silva to fight Sonnen and then I think we'll have a better idea.

I wanted to wait to give my opinion, but I just can't hold it back lol.  I have to go with GSP on this one.  Silva is arguably the greatest striker in MMA history (I think a prime Crocop is another possibility there), and he has a great record in the UFC.  However, I just think GSP is better in so many more ways.  He's a more complete fighter than Silva is, he is a better athlete than Silva is, and he's fought the better fighters than Silva.  Also, I think Silva's losses impact his greatness more than GSP's do.  I won't count the DQ loss to Okami against Silva, but GSP lost to better competition in Hughes & Serra.
 
I will say that if Silva decided to move up to 205 & dominated there, I would have to rethink my position (that's assuming GSP doesn't move up to 185 to dominate though).

I agree with you on your assesment completely. That one submission that Silva got caught with in Pride was insane. I somehow feel like GSP is more serious and business like.