Some good game soundtracks to get?

Assassins Creed 3 has some pretty good soundtracks in my opinion... .3.

Metro 2033

Binding of Isaac

Guilty Gear

Ducati World Championship

Carmageddon

Dustforce. I've listened to it for a week the first time.

Hotline Miami has a brilliant soundtrack. As does FTL.

Bastion

Portal
Portal 2
Cave Story +
Sonic Generations

Crysis 2

LPO - The Greatest Video Game Music 1,2

Darksiders 2 - #1 #2 #3

Hotline Miami and Assassin's Creed 2

Tiny & Big: Grandpa's Leftovers

• Deux Ex: Human Revolution
• Diablo series
• Assassin's Creed series
• Halo series
• Portal 2
• Silent Hill 1-3

If you don't mind Jeremy Soule's works, he can put out some great tracks. His most recent would be in Skyrim & Guild Wars 2 (and I think, WoW's last expansion?), so those are definitely accessible on Youtube for previewing.

Xenoblade & NieR aren't to be missed when mentioning video game music. Indie-wise, Dustforce, Super Meat Boy/Binding of Isaac (same artist), Shatter, Spacechem (freely available), Dear Esther (h/t friend for raving about it), Retro City Rampage, Braid, Machinarium and Trine/2. Hotline Miami can either be molten gold on your ears or chalk on blackboard. S&S EP can feel awkwardly minimalist, but do listen to #26 "And We Got Older" before passing judgment.

Handheld-wise, The World Ends With You has some of the most unique music to bless modern gaming, but it seems like you'll have to play the game to get why it's so fantastic. Most of the licensed music in Little Big Planet ain't bad at all but I don't believe they've managed to compile all of them due to the licensing. The Layton series has wonderfully arranged musical accompaniments and is definitely worth a listen even if you hate everything puzzly.

Let's see how many I can think of, off the top of my head.

Bastion

Binding of Isaac

Awesomenauts

Super Meat Boy

To The Moon

Psychonauts

Frozen Synapse

Portal 1+2

Half Life 2 (great ambient music)

FTL: Faster Than Light

Retro City Rampage

Final Fantasy IX (What? You didn't limit it to just PC!)

Beat Hazard Ultra.

Soulcaster

Mass Effect 2 example

Binding of Isaac example

Hotline Miami example

Bastion example

Torchlight 2 full soundtrack

PAYDAY: The Heist Soundtrack

The Witcher 1 + 2

Bastion.

Any of the Halo games. I personally hate the games themselves, but the music is beautiful.

Legend of Grimrock

Dragon Age