What games should I get?

Bad Rats

Dustforce

This war of mine

Look only in the 12 hour deals on steam. get anything u fancy. terraria, gary's mod like small games or if only want one big one then Lord of the Fallen

The Bioshock series is a personal favorite. Infinite was amazing, 2 is still broken for multiplayer if I recall correctly, and 1 is still really good.

Well, you could view my wishlist for some ideas winks.

But in all seriousness, looks like you spent quite abit of time into Dayz and Unturned so perhaps Project Zomboid?

I would recommend Dues Ex HR, Alan Wake, Sleeping Dogs and State of Decay. Each fit into your current budget. Have a Merry Christmas!

If you don't have a Witcher i think it will be a good choice.

I recommend something that you could get a lot of hours out of. How about Kerbal Space Program? (If you have enough for it).

If you like building things, testing and tinkering with them (and want to watch some poor little green guys helplessly fall out of the sky to their doom due to your mistakes), or even just love the idea of flying off into space and reaching other planets, it's something that is definitely worth spending the money on. The game is even better when you add a bunch of really great mods to it as well.

for 3 hours newest NFS (Need For Speed: Hot Pursuit) will be for 3$ after 80% community discount (at Steam ofc)
also theres Marlow Briggs and the Mask of Death (1$ only), and it seems that you haven't any The Witcher game so you may wait, both will be for 1,5/3$ when all good discounted price will be back on last day of winter sale.

you may check nuuvem (brasilian store, portuguese language, but easy to use) http://www.nuuvem.com.br/produtos/promo/1/order/price/page/3
Hotline Miami 0.75$, Alien vs Predator (2010) 1.3$, Aliens Colonial Marines <2$, Mirrors Edge 1.2$, Max Payne 1+2 for 2$, old classy GTA (3, VC) for 1.4$ each and more.

you are fortunatelly bcos atm not many games is in your steam library, so you got many possibilities. I advise you to buy as much as possible heavily discounted AAA/AA+ games, for 20£ you can buy even circa 15 new games. the greater the choice you have the greater the chance that there will be something you'll like it.

alse here (keyshop) http://www.simplycdkeys.com/steam you may take some nice games for 0,5£ (I warn you, Fuel is crap)

Get Wasteland 2 for 30€/$ at indigala (yes 1$=1€ in Europe, they love to *** us.), you'll get The Evil Within as a "bonus", that makes approx 15€/$game which is a very good deal on these 2 games! That was my Christmas gift to me :)

Arma

CS:GO

As I said, on Steam atm:
NFS Hot Pursuit 3$

also if you like racing games:
NFS Undercover 2$
NFS Shift 3$
NFS Shift 2 4$
Ridge Racer Unbounded 2.5$ (IMO crap;)

LEGO Batman and Lego Hobbit 3.5$
Super Meat Boy 0.7$