I agree with fastair. Never actually bought anything there, but seems to have a good selection of stuff.
I actually on my last trip forget headphones, and as usual, left from CVG T2. With almost nothing there, thought i was going to be SOL, but then realized they put one of those Best Buy express (or whatever they call them) machines there. I never understood why they had those things there - but all of a sudden - made so much sense.