The classics still live on. I don't think any girl will ever appear that is better than Kari Sweets.
However, here's the top three hottest newer solo models out there right now IMO
London Hart -
http://www.londonhart.com
Lily Luvs -
http://lilyluvs.com
Teen Kasia -
http://teenkasia.com (I've always been partial to PF's photography)