I spend most of my time these days on private networks, but I'm also in #startups on Freenode. Lots of good conversation in there, and a lot of HN regulars.
No better way to find out than to give it a shot!
Used to always be on EFnet for Symbian chat but the best Android chat is on Freenode so that's where I go now.
Edit: Internet Relay Chat chat. Sorry. Couldn't help myself.