You know, I cheerfully admit to being an utter fucking newbie in the domain name game. I've never bought or sold a domain name for profit. All I know is what I've discovered while registering domains for my own use.
And what I have learned is this: whatever your website concept, it's not very hard to find a two word domain that's good. Any motherfucker who is good with words can find a two-word domain that's not taken yet. It takes a little more work to find two nice short appropriate words that sit pleasantly together in a domain name, but so far I've never had any trouble.
Which means this: I'm having a very hard time imagining ever wanting to pay more than registration fees for a three word domain. Especially when none of the words are "sex".
My

.