I have three favorites of forum types to use and setup.
I use phpBB for situations where i need very indepth permission sets, such as a support forum.
I use SMF for situations where i need automated member promotions for rewarding a member for amount of posts or amount of time as a member.
I use this for a fun forum where socializing is the norm versus technical. Also this forum i find to be quick and easy to setup and go live in a short amount of time.