Searching Tower Defense and Paradox Games | Sharing Steam Keys

I've had a lot of fun with Starship Defense from DSiWare

Sanctum is a first person tower defense game, it's very nice.. and also Sanctum 2 is coming soon.

Tower Defense games that I could recommend You are:
Dungeon Defenders;
Sanctum;
Earth Defense Force: Insect Armageddon;
Orcs Must Die! 1 and Orcs Must Die! 2 (I haven't played them yet but heard good things about them).

Hope You will find something interesting :)

Not sure if anyone else suggested this.

Anomaly Warzone Earth is pretty interesting. It's a reverse tower defense style. More like tower offense. But do check it out. :)

Games developped by Paradox :3 ?
Crusader Kings II (my favorite game ever), Europa Universalis III, Victoria II, Hearts of Iron III, March of the Eagles, Europa Universalis: Rome... (and their predecessors of course)

Games only published by Paradox (grouping them by dev studio) ?
Majesty 2
Mount&Blade
Dungeonland
Magicka, The Showdown Effect
Supreme Ruler series
Defenders of Ardania (which is a TD/RTS hybrid, so you'll probably like it :P)
Starvoid, A Game of Dwarves

I probably forgot some :3

Maybe you should try Sang-Froid - Tales of Werewolves?

wut

warcraft 3 tower defense mods

Sanctum has my vote. IF you like it, do check out Sanctum 2 due later this year.

You can play StarForge as FPS Tower Defense game (take a look at the gameplay videos).

There have already been mentioned a lot TD games, so here are the other Steam TD games I can think of:

Monster Mash

Those are both "TD-like":
Alien Hallway
Sword & Soldiers

So far I had a lot of fun with the free "Bloons Tower Defense" series (flash games), you should try them if you didn't already ;)

And maybe you can get your hands on a Desura key of "Beware Planet Earth" from a bundle, because afaik they should give Steam keys.

Another nice TD game that is not yet on Steam: McDroid

Defender's Quest: Valley of the Forgotten is a seriously great tower defense game. It includes some RPG-like features such as characters that serve as your units--warrior, archer, and mage-types are all present--which can be leveled up to increase their potency. It's even got a surprisingly good story told through cutscenes. Highly recommended.

try kingdom rush, i know it's online but it's different from most of the ones online. Try it out, it is really good. Also if you really don't want to play online TD you can try revenge of the titans which is on steam and i really liked.

CreepTD is an great multiplayer tower defense game.
There are a lot of amazing flash tower defense games. Just give them a try.

bye

defenders of ardania is a tower defense game by paradox
http://store.steampowered.com/app/73060/
I don't own it so can't say if its good personally, but it seems to fit both your categories.(by that I mean 1towerdefense and 2paradox)

Defender Quest: Valley of the forgotten

Edit: oh,was already mentioned. Still a great game.

List I found of a few Greenlight Tower Defense games. link Not my normal type of game so no clue which ones are truly good or not.