sweatdrop Kitty mostly uses modthesims.
But here are a few others that I use.
1,2,3
XM Sims Some of their older stuff is not too exciting, but their new stuff is quite nice and they have such an amazing range of hair colors.
The site for ancient Korean downloads.
2,3
Club Crimsym Eye-popping fantastic textures and some slick meshes, a little on the gothy side but that never hurt anyone.
1,2,3
Parsimonous If you like aliens, you'll love parsimonious. The patterns on the clothing are extremely avant-garde, which is kind of cool. I love the houses there, though.
2
Sims 2 Graveyard Hard to navigate, but you can find things there from dead sites, which means that it's the only place on the internet to get most of the downloads there. Check out Helga.
2
Vita Sims A lot of the clothing there is too trendy for my taste, but the textures are okay and the furniture is really classy.
2
Sims in Paris Mostly objects, and a little hard to use because many of the meshes aren't centered the way you'd expect; and the item names and descriptions are not very creative, but once they're placed in your house, they look really classy.
I will warn you off the beds, though. They are classy looking beds, but the bedding isn't animated.