A friend just asked me what .Net groups are good these days. Atlanta is the Software Capital of the South which means we have many great groups in town and I watch them all for interesting topics, but these are the three I personally attend most often:
http://www.meetup.com/AtlAltDotNet/ this is great for new ideas and decent technical depth. It is a fairly new group still finding its feet
http://www.iasahome.org/web/atlanta Atlanta's IASA chapter - always has super-smart people in attendance. Most meetings end up being a discussion (or argument!) with few punches pulled. The best part? BS artists are shot down very quickly and most never come back :)
http://www.atldotnet.org this is the 'main' .Net User Group in town and excellent at delivering high level introductions to topics. Networking is very good here too as local MVPs etc are at most meetings
Other .Net focused groups are www.atlantamspros.com (now defunct) and http://ggmug.com.
Hopefully that helps a few people looking to learn more and network :)