Borderlands 2 is quality. Great humour, massive improvement over the original, and is a major time-sink.

They can be a little buggy but I couldn't recommend the 2 Star Wars: Knights of the Old Republic games enough. If you're a fan of the Star Wars universe they're a must play, and if you're not then they're still awesome if you like Bioware style RPG's.

The Mass Effect trilogy.

I don't know if this counts as indie but if you're looking for a game to sink your teeth into you should check out Don't Starve. You can easily lose hours upon hours playing this game and the re-playability is top notch.

Bioshock: Infinite. I just smurfing love that game. It's actually been too long since I played it, I'm definitely due for another run through.