You might want to look at papers, please, as something different

Thanks everyone for the suggestions!

I'm actually considering KOTOR, but I've heard the combat is clunky. Is that true?

I was just about to suggest it and in my view it is a bit clunky, but still a good game. I have no idea how KOTOR 2 is but given the recent widescreen update I think you should have a look at that as well.

Also one of my favorite games, Alpha Protocol. It's an espionage RPG developed by Obsidian and it has a nice choice system as well, including the fact that the order in which you approach your missions changes things in other missions and also in how you encounter different characters for the first time. Dialog system is quite close to the Mass Effect one. Unfortunately it's only available on Steam (which is wrong, see below)

Edit: Like Grargar said below it is available DRM-free over here

...Mafia? ;)

Edit: I suppose that one makes rather heavy use of memory, though.

No.

There is a bit of work-around involved to get the standalone installer, but once downloaded (along with the patch that the site offers you), you don't need internet anymore.

Thanks for the clarification. Now I genuinely can't understand why SEGA can't bring it to GOG since they are already selling the DRM-free version elsewhere.

Cool beans! I'll look into it! :)