The big ones are:
SmartScripts Tube script
Nubiles
TEVS
and
TubeAce
there are, of course, others..
don't forget to grab our tube clips from:
SpunkBucks.com and
PornoPayouts.com
we're adding new clips daily.. and have full featured exporter as well as auto-updating XML/Nubiles feeds that will keep your tube script updated with our latest content automatically... ;)