In terms of attitude to sex and lack of inhibition I'd say Lindsay Lohan, Kim Kardashian, Courtney Stodden,
Zahia Dehar. Carmen Electra and Jenny McCarthy were built that way and always talk a good game, who knows what the performance would actually be like though.
For anyone that doesn't know Zahia, she is a former teen prostitute that found fame after it was alleged that former French international footballers (including a certain Z.Z.) saw her when she was underage. She now models and fashion designs, and looks like this :
http://ris.fashion.telegraph.co.uk/.../1/TMG9038959/m/Zahia-Dehar-vmag_2119513a.jpg
These days I'd love to see Cameron Diaz or Pamela Anderson in the "friends slutty mum" role, although Pam has proven on camera that she is strictly lying flat on her back making crap fake noises.
Strictly in terms of physical appearances, a pornstar blessed with the looks of Mila Kunis, Megan Fox, Kristen Stewart would work for me. There is always a market for a waif like Kristen, I'd love to see Mila perform a POV blowjob, and I have repeated fantasies about Megan and Sasha Grey embarking on an extended sensual girl-girl with plenty of deep kissing and stroking.
And in terms of body types, I'd love to see Christina Hendricks, Scarlett Johansson, Kat Dennings or Kelly Brook fucked all over the shop, tits flying around wildly.