Looking to upgrade my video card, suggestions?

First, sorry for the long post that's about to follow.
Second, here are my specs.

Mobo: MSI P67A-GD65
Ram: DDR3 SDRAM 8 GB
Processor: Intel Core i5-2500K Sandy Bridge 3.3GHz
PSU: 550w
Video Card: Radeon HD 4670 1GB (Crossfire ready)

So when I built this computer last year, I wasn't planning on gaming at all really. So I didn't buy the greatest video card. Recently with all the steam sales going on and being a CAG, I've picked up quite a few games. Just about everything I've played has run ok, but Alan Wake seems to be having a little trouble, and L.A. Noire as well.

So I'm looking to upgrade my video card for the next few years. Fortunately, being a CAG means I won't be buying the latest greatest games until they're very cheap ($5 to $10), and my monitor only supports up to 1920 x 1080.

Any suggestions for a decent priced card that'll last for a few years? Thanks!

PS: Would it be a better idea to get another 4670 for Crossfire? I'm very new to all of this.

What's your budget? I'd say either a 6850 or 6870. 6850 is around $120-150ish while a 6870 is about $170-180ish.

The 7750 is about 120ish, but the 6850 should mop the floor with it.

Says 6850 ~ (2x) 4870

So I'd skip trying to find another 4670.

6850 vs 7750

Im with Jmbrci with this one, I would go with the 6850, or the 6870 if you want to spend more money for more performance.

PC Gamer says the 7770 line is the best value right now.

I'm not sure your psu could handle it but I have a really similar set up with a gtx 560 ti and love it. You might be able to catch it on sale for around $200.

$120-$150 doesn't seem too bad. I'll look into these options. Thanks!

[quote name='pacifickarma']PC Gamer says the 7770 line is the best value right now.[/QUOTE]

PC Gamer, Wikipedia...almost the same value except I cannot go back with my history-eraser button on PC Gamer.

It may be the best value on the "current" line of cards, but not the best value out of available cards. The 6850 will give better performance for the same cost or less. Spend a bit more and you get the 6870. I will confess that I am still running my 6870 that I purchased about 16 months ago. Still a great card and my only thought of doing an upgrade is if I want to run some ridiculous resolution on my setup (like 5760 x 1080).

6850 vs 7770