I know you said you like shooters and not RPGs, but give Titan Quest / Immortal Throne a look. On sale, they can be found together for $5-10.
If you ignore the RPG elements (since the story is fairly weak, the map is very linear, and skill progression is really simple), you can look at it like a general hack-and-slash game where you just run around killing stuff. It's quite fun that way. You can just spell points in whatever skills / attributes sound good, and though your character will suck in the end game, you'll have a lot of fun in the mean time.
Torchlight is similar in this regard. Mindless hack and slash.