http://www.biminibucks.com Niko and Mikie are great and honest and the sites in the program are excellent.
http://www.cashtitans.com Jim and Shane ROCK and if you have hardcore traffic it is perfect for CumOnHerFace!
http://www.intensecash.com If you have gay traffic, make sure some of it ends up here! They have a popular new site that is converting like mad
http://www.brokestraightboys.com
If they are accepting webmasters (very new), jump on
http://www.innocenthigh.com - mad conversions and the owners are some of the nicest, hardest working guys in porn.
Those are just a few of my favorite NATS programs. All are underpromoted, IMHO.
Brad