Ours is on it's last leg too. Last week it barfed out something (looked like nylon tape or something) and it clogged the hot water line in the shower. My day is coming soon!
This is a time not to be a cheap bastard though. The ones with better warranties are built better and are also better insulated so they'll be cheaper to operate. Plus they're not that much more than the cheapies. Keep that in mind.