I went through that during my undergrad and it's even worse now. In college what helped was playing the multiplayer games... racing, fighting, first person shooters. My friends and I had so much fun with halo, snk vs capcom 2, burnout, etc...
I tried playing an rpg on xbox 360 about a year and a half ago... Lost Odyssey. Really great game, but finding a save point would take so long sometimes that I just had to give it up. I live a lifestyle where I can't really wait an hour for the next save point and I feel to old (27) to be playing psp or nintendo ds in public.
The thing about fighting games though is that I only have fun when I play them with friends. You can also try other games that are fun and have frequent save points. I really am liking wolverine for the xbox 360, mirror's edge, street fighter 4, castle crashers was a lot of fun when my brother and friends came to visit.
So yeah, I think we're at the point in our lives where spending 30 hours on a game is really just not something we can do. But if you're willing to go back to older games, many of those emulators let you save at any point (snes, gameboy, genesis, psOne, some on ps2, dreamcast, etc..). I remember when I was in middle school and high school I would spend hours playing non-stop. Homework and games, then later homework, partime work and games, then college, studying, work, and games, now wife, gradschool, work, and arcade cab project, later... kids, wife, real job, and uhh portable in the bathroom?
I really don't know how you guys find time to play when you have kids, maybe it gets better when they are older because you can play the games with them?