MSI ATI RADEON R5770 HAWK

It would be an overkill for both those processor but could be a start of a part by part upgrade. I would not bother to change over to the opty 165 unless you get it almost free, it is a great CPU and should be able to overclock good 2.6-2.8GHz usually.
If you are paying a premium for it you can get DDR2 or 3 ram, Mobo and CPU(Athlon II) for about ~$200 today which would be a better choice

The Opteron 165 only has a clock speed of 1.8GHz. Even though it has more cache, it's not really an upgrade due to the low multiplier. Since your CPU would generally be the limiting factor (even if you OC the 165 to 2.3GHz) I think that most of the time you wouldn't get much of an increase over your 9600GT. You're better off upgrading your motherboard, RAM, and CPU while keeping your 9600GT

I'm with rolli on this one. Unless you're planning on upgrading your CPU/MOBO within 4 months, you're going to want an HD5670.

I pretty much agree with everyone else. I would update your your motherboard / CPU before looking at an upgrade path for your video card.

Well thanks anyways guys, but is there a better Graphics card out there then my NVIDIA 9600 for my system?

There's tons of cards, but the problem is that none of the cards would be fully utilized by your system.

While this may be true, its not a reason to *not* get that card. You will still get excellent performance out of it, far more than you'll get with a 5670 or lower card.
If you then either upgrade or further OC your processor, your video card can utilize that and your performance will increase.

My rig is fast, but I still game at 1280x1024 and guess what, I use a 5870. I know its overkill and underused, but it plays better than any other lower video card. Whenever I get a larger lcd or want to use my lcd tv at higher res, i'm already covered.

EDIT: Another thing, IF and only IF this comes down to budget would I suggest going with a lower card. The 5770 is cheap enough and an enourmous price/performance value at ~$155. It makes no sense to spend $90-$100 on a lower card that you'll end up having to upgrade sooner when you upgrade the rest of your system eventually.

hardware -> If I were to replace your HD5870 with an HD5770, you'd never know the difference.

Unless you're using a Core i7 or Phenom II OC'd. Any dual-core will be frame bottlenecked, and if you're not using a high-end processor, downgrading will yield an unnoticeable performance loss.