I suppose I'm in the same "group" as TheWesDude, in that I don't really buy gimmicky items over the net to "nerd out" over, but I do get a great sense to joy out of purchasing sweet components for a new system I'm building. The last time I built a PC (the one I'm currently using), I derived both disappointment and extreme joy in determining that this CPU just wouldn't do but THIS CPU will kick ass; that this motherboard is just too small and has too few slots for memory and additional cards but THIS motherboard looks like it'll do quite nicely! I suppose I somewhat "nerded out" each time I got a specific component, but it was only when it was all assembled together, and all the extra parts sold to friends who didn't need as demanding performance from their systems as me, that I really felt happy as fuck. Right now I'm still in the (really, REALLY slow) researching phase, but I'm gonna be grabbing some peripherals (like new mouse and such) pretty soon, which I'm taking my sweet time being choosey over.
If anything, the most gratifying purchases I've ever made were from over-the-counter buys. Chiefest among all my memories was buying SOMETHING (I don't even remember what) at Fry's, and seeing the dual jewel box FO1/FO2 combo at the counter by the register, which I quickly snagged a copy of an bought post-haste! No longer did I need to rely on borrowing my friend's copy (not that I had to very often, thanks to HUMONGOUS! install), I now owned the greatest RPGs ever of all time, myself! I was very happy, that day. =D