I use Xfire and have done for a couple of years now. Username: dajmin
My profile:
http://www.xfire.com/profile/dajmin/
It's not that useful for LFS, but as Ben said in other games it tracks servers you've joined. It also let's you see and join the servers your friends are on if you want to.
Never had any problems with it crashing except in Everquest, but that was related to a Sony patch not Xfire. And I don't use the auto-download feature.
It has about a 12Mb footprint, so if (like Boosted) you consider that "a lot" of RAM you probably shouldn't be trying to play games anyway, and certainly not with any other apps running.
I originally installed it for the logging of how long you've played games, but I later found that it was really useful when my brother and I used to play Wolfie:ET, since we didn't have to pre-arrange which server we were joining, we'd just One-Click Join when one of us found a good one.
The chat feature is also useful if you want to say something to someone outside of the game. We often use it to bitch about people when we're playing the same game. But since the UI can overlay games, it means my brother can talk to me any time, whether we're playing the same game or not. And unlike using the MSN method, you don't need to set it up to beep every time you get a message - it just pops up a little window (which you can reposition and resize) on top of your game.
I like it a lot, never had a problem. Highly recommend it for people who have friends who like different games
oh and we have a little smapperbox over at our 