Aww, you were in St. Louis, Ellebeth? Me too!! It was a great show! Such a good one to be your first! I've met a lot of people in the last couple of days who said it was their first BSB show! I love that!!
As far as your question goes... for me, it honestly depends on what I'm writing. If I'm writing depressing, angsty stuff (and I usually am), seeing them in concert doesn't usually help - in fact, it kinda kills my writing mood because how can I torture them after seeing them so happy and healthy and intact? It's hard!!! Like right now, I am on such a Kevin high from this weekend that there is no way I would be able to go and write a scene about him in Guilty Roads, where he's currently in a vegetative state from being shot in the head LOL. Hell no, not happening! But if I had a happy, bromantic story going on (and I don't), the post-concert high would probably help inspire me.