Well I have had my WRT54G just on linksys firmware through comcast for years and never had a problem with it and I never had to reboot it other than when making changes and I run torrents almost nonstop.
The person I am getting this is not a power user in any sense of the word. So I think it would be overkill to add all that for them. I sent them a WRT54GL cuz like you I think Linux is the way to go. I don't want to be their tech support so I left it stock so if they have a problem they can call Linksys and not me. lol My parents and brother keep me busy enough with their problems.
Good choice! Yes, I presume Linksys has worked some of the bugs out of their official firmware by now. But if there's ever a problem you have options. I like options. You would be amazed how a router may work perfectly for one person in a certain configuration, and be completely unstable and unworkable for another.
-- Rob -- Laser eye surgery rocks! I love frickin' laser beams.