I agree with Nooch on working with the LBS. Things may go funky (it has with everyone I know) and you swing by the LBS and they help you out fast. Paying the extra is worth it for me. From what I hear, there are issues with certain shifters (Shimano 105 triples--the left one) breaking, frame "breaks" (mine looked like it had a scratch--which also looked like a carbon fiber scratch--likely wasn't, but the bike shop helped me out and swapped frames on warranty), etc that will be easier to deal with at a LBS rather than online.

My LBS even tuned my bike up for the life of the bike, while all the other ones at least tune them up after the first few hundred miles for free. You can't do that with the online ones. The cost savings of going online will shrink the longer you own your bike, I'm certain of it.