Paypal.
Just look at other large XXX sites and see what they use. Just check their traffic stats with compete.com / alexa.com first to make sure they're actually getting traffic and that they are a big site. That way you can rest assure their payment processor is legit as a big site wouldn't be stupid enough to use a crappy payment processor.
* Compete may only show data for US traffic I believe so it might look lower. Just keep that in mind.
http://www.xbiz.com/directory/showcase.php?ref_id=5
If you start with small website, i mean if ur website is more like personal porn website. then better used ccbill.
Whoever put "PAYPAL DO NOT ALLOW ADULT CONTENT." - You are a real dumbass. I said "I was being sracastic." dummy. Learn how to read.