http://www.nwvault.com is the main site to download NWN modules from.
If you like building your own adventures NWN is the way to go. It has a really powerful editor to create modules. Content is not limited by Bioware and a lot of people create new stuff for it, like new models, classes.
From what I hear ToEE is really bugged, which was a reason I wouldn't buy it. Also support seems to be not very good, as gamers had a patch earlier than the company