Mass Effect just hit $20. I can get Fallout 3 brand-new from Blockbuster for $30. Which should I get first? I will probably only play through either game once - I've never been much for replaying games.

1. About how long are both games each?

2. How large is each game? I've only got a 20g drive - got Fable II on there with some other stuff - 3.?g left. Obviously Fable II will be removed, but if I can install both, hey, great.

3. How buggy are they out of the box? Are things improved by updates?

4. How easy is it to get lost in the game? Morrowind was too much for me, most JRPG's too restrictive, but KOTOR was just right.

5. Which is more "casual play" friendly? I'd rather have a game that's "just 10 more minutes"-ish than "set aside an hour or two."

I need to finish Fable 2 first, mind you. I don't know when I'll get either one, to be honest. I'd like to go to England this year, and that means getting *really* tight on my budget, so...