Yes the patch fixed most of the bugs and it no longer freezes when people sign in. So you can stay signed into the PSN without worries. Also Trophies as you stated.

Im on my 3rd play through now. Trying for a neutral ending as i already finished it with the evil and good endings.

Congrats leo-j. There is no mandatory install, and I didn't see an option for an install. This game is excellent, and its the best RPG on the PS3, imo. The trophies are pretty easy to get.

It doesn't freeze when people sign in or out however it does freeze/slow down & stutter if you play it for too long.

Great game though.

Fallout 3 = awesome! No install. Trophie patch! And patch for problems!... So works fine. Oh, and did I say the game looks godly and the line of sight is ENORMOUS!

I Played it a little and had only 1Gb available space. I guess it just caching some files from time to time, but 5gb ... it is too much.

I just play it - no installs. But I bet its got a cache going - I'm sure Oblivion did. So the minimum HDD is probably a warning it going to use some HDD to cache but not install.

It has background installs you'll rarely notice except for the occasional load/timer thing from time to time. It's an amazing game, I had a little fun with it when I checked it out now I'm getting it for Christmas, I looked at my install file for it and it's about 1gig now so it's installing just it's installing while you're playing which if there has to be installs I think it's one badass and only way to do it.