I think I played about 80 hours on my first character but I haven't played it much since then. I managed to screw up the story a bit by finding the father before I was supposed to
Still I enjoyed it, but not so much for the main story as all the other stuff. I loved going around exploring stuff and finding logs in the computers that told stories from people just after the bombs had dropped etc.I enjoyed it a bit more than Oblivion, it just felt a lot more polished even if it still had it's flaws.
I haven't modded it much myself (cause it runs kinda crap on my computer, if I shoot more than a few bullets with the rifles the game slows to a crawl), but the mods I did download was a lot of fun. Bullet time ftw