Pidgin has always been my favourite chat program, and I've stuck with it even after Gnome switched to Empathy, partly out of habit, but also because it has the ability to block messages from people I don't know, and the ability to show email messages from web email applications and quickly go to the email page.
I've moved to Fedora 15 because I want to use Gnome 3, and I'm giving Empathy another go. I'm using Gmail to check my old and little-used web email accounts like Hotmail, and unless I get start getting annoying spam with Empathy, I might stick with it.
Empathy uses Gnome 3's new bottom-of-the-screen notification system. Apparently Pidgin doesn't, but there's a Gnome 3 extension that allows Pidgin to integrate. Hubfolio has a guide. I may be checking it out if the spammers find me.