All my friends are gamers and muscians, so I don't get embarrassed about talking about LFS or whatever other hobbies with them. My girlfriend of 5 years is a computer nerd too so games don't bother her much outside of the fact that "I'm not paying attention" to her. We've got an oldschool NES and about 40 games that we sometimes play together, but she can't get into the "stupid 3d games."
When we first started dating I was a total Everquest geek in a high level raiding guild, so I don't think it can get much worse than that. I ended up quitting EQ to save the relationship lol
Games become 10E23 * more than geeky when you change RL plans around raiding Rallos Zek and trying to get new swords with +10 to beastslaying and camping Vex Thall shards and crap
Later I eventually got into World of Warcraft and ended up in the same guild that I was in in EQ and was at the end-game level there too before I spontaneously quit. My old lady was ok with WoW as long as I never played it at home... I got caught red-handed a couple times though.
As I'm not in a league or anything and just LFS in my spare time, I don't think it's too geeky, but that opinion would probably change if I found myself saying things like, "I don't know man, I'd love to hang out but I'm signed up for a race ... err... I mean I have plans, sorry!" I guess it wouldn't be that bad though, I mean I already make plans to play games with my friends i.e. "OK dude I'm heading home, I'll look you up in Day of Defeat in about half an hour," but I think it'd be different with a game that no one I know IRL plays. (I can't get anyone to play LFS; maybe because I couldn't bring myself to recommend it without investing in a wheel and stuff.)
But yeah, if I were single and trying to "woo" a pretty young lady, I don't think LFS, CS:S, or DoD:S would come up in conversation unless I already knew it would be "cool." Much better to talk about playing guitar and drums. Gamer/nerdy chicks FTW!