Hostgator Forum Options

[orbit]

I want to ad a free forum for basic users and a private forum for users who have bought my program.

Hostgator has 4 free options. I want something fairly customizable, which would you use?

phpBB
Simple Machines Forum
bbPress
PunBB

[Limelike]

phpBB

[greentitanium]

agree with above

[razorfish]

phpbb cos you can find any plugin you want if in the future you need to extend it with more capabilities...