I love DieselAction sites - haven't seen their members areas but the design and high quality pictures caught my eye straight away.
SashaFucksDasha.com is my favourite. I'm not usually a fan of girl/girl sites, in fact I hate them, but this site feels different... I guess it's the idea of it being "100% real" like they say on the DieselAction affiliate program site. I'm completely straight, but I'm a sucker for great looking design and pretty pictures
And I've only been inside two members areas, my own and
KatesPlayground's, and I check for new Kate updates nearly every day
So there's my two favourite paysites!