domain Site appraisal needed

[tytanic11]

The site I'm looking to sell is an adult site so I won't post the URL here [PM me if you want it], but it's by far my largest site. We've had 900,000 hits in the month of March so far, about 1.1 million in February. We also average about 40,000 unique users per month. We've got a free photo gallery, with over 9000 user contributed photos, and almost 15,000 registered users. We've also got a forum, seperate from the gallery, with 3000 registered usrs and 13,000 posts. The site currently ranks 146,674 in Alexa, and some pages have a PageRank of 3. We run a 'members only' type section with several hundred members, all of whom paid $15 each to join. In the past month, that's made us $175 - the site also has roughly $60/mo from AdBrite ads. Considering the size of this site and the amount of traffic, what would be a fair price to sell it for? I do understand it's hard to do an appraisal without the domain, but it doesn't feel appropriate posting it here - again, PM me if you'd like to know the domain.