If it's just for personal use then phpBB should more then enough since it's IMO the best free option out there..
I haven't tested phpBB 3.0 myself yet since it's a couple of years since I used it myself, but used the previous version for 2-3 year on a fairly large forum (200k+ posts) without any problems..
www.phpbb.com
But for a more serious/"professional" forum then I would recommend vBulletin since it's simply the best forum script out there, but for $160 it's a bit too pricey for most personal forums..
www.vbulletin.com
Both scripts are easy to install and maintain and there are tons of free modifications for both forum scripts out there, and most of them are free so there's really not much difference there..
But the main difference between them are (again IMO) that vBulletin is a professional script with much better admin features and options, the security is better, and it's also very easy to upgrade and install new modifications/hacks etc.
Datalk.com runs on a modified version of vBulletin by the way..
