I don't think anyone around here is going to shun you, just because you bought a game at full retail price. Sometimes there's a game that you just aren't willing to wait on buying. It happens to the best of us.
For me, back catalog never even figures into such a decision. My back catalog is immense, and high-quality. I'm never hurting for good games to play. This makes it a lot easier to wait on new titles. On the other hand, even I am susceptible to an early purchase.
I recently picked up a copy of the Retro Game Challenge for my DS, at full retail price. Granted, this was just $30, but it was brand-new and full MSRP. I bought that game new at full retail because I agreed with what the developer was doing with it, and wanted to support them. Also, I love me some retro-gaming, and that title definitely delivers in that regard. (it felt like 1989 all over again)
I am also very stupid when it comes to games whose stories and/or characters I really enjoy. I payed full retail for Legacy of Kain: Defiance. And I pay full retail for every Phoenix Wright game that comes out.