Intuitive help desk / ticket system application?
 

Preferably something open source, but I'll pay for something if it's good.

I've used Kayako before, it was ok. I'm looking at some other open source options like OTRS.org...

This will be used for standard website support (technical, general, billing, etc).

Any suggestions?

Its not open source, but we use LiveHelpNow. I have tried Kayako before and others and really prefer LHN.. it's around 20$/month for the chat and ticket system.

open source sucks for that.

http://www.zendesk.com

that looks pretty solid.. thanks!

Yups zendesk.com is the best, it's what twitter, groupon, etc. use.