I have a bit of an underwear fetish, I must admit. I've probably got over 30 pairs. But I love it, there's something about a sexy pair of pants that makes me feel good, and it's really the only 'fashion' item that I ever get excited about.
I don't wear jockstraps for the gym though. I pretty much treat them the same way a woman treats lingerie, i.e. they are for the bedroom
My favourite brand is Aussiebum, I probably buy on average 1 item per month. Also like their swimming trunks (got 3 pairs - skimpy, square cut, and board shorts)
I really like the new jock brief style that I've seen, which are basically briefs but with the ass exposed. Aussiebum don't do styles like this yet, but when they do (surely a matter of time) I'll be snapping them up!