Adult virgins and those keen to date them.

Many people are shy/embarrassed about their (our) chaste status and being able to jump that hurdle before you even meet could be a big plus.

It could be seen as trawling the shallow end of the genepool, but many people believe this of dating sites in general.

Music? It's a reasonable indicator of lifestyle choice (so good chance of bringing compatible people together), not male dominated and it could be multiple niches (adding up to something on a much bigger scale).

The thing I don't get with all dating sites is they all seem to be exactly the same - mediocre design, some plugged in dating script. I can't tell if this means there's room in the marketplace if you did it the right way or if it's just totally over-saturated.

A dating site that caters to atheists and agnostics.

Hmm:

Dancers: (per city) They've probably seen each other at clubs. Should at least peak people's curiosity.

Geek/gaming: Gender's pretty even in online gaming these days. God knows they could use the help :-)

Specific sports: Martial arts, running, bicycling, etc. Gives people more to talk about than usual. E.g. Okinawan Karate or Trek bicycles.

World of Warcraft would probably be a good one, even if the ratio of males to females is higher than 1 to 1.

hmmm...I think the problem with the big niches is they tend to be either heavily female or heavily male.

My friend I came up with the idea of a dating site based on what your fashion sense is - t-shirts/casual personalities being more compatible.

With this type of thing heavily female is not a problem -- if you get the women, the men will come. It's why OKCupid's design is pink.

The ratio of active, real men:women for online dating is 10:1 or sometimes 100:1. So targeting heavily female niches is fine. The men will find it.

Yeah, that's actually a really good point. I can't think of any good examples though where this would work. Like if you go to Borders and look at their magazine racks, there are tons of specific niches that cater to mostly, if not all, female (there are like 8 different magazines on knitting), but I'm having trouble seeing how you could apply it in the dating realm.

considering my surroundings are 99% web-savvy hipsters (i'd call myself a hickster), i'd suggest "bars, bands and blogs" or "bars, bands, and bookmarks"

my favourite favourite idea was a dating site that focussed on stuff you /didn't/ like.