Hi Bass,
My GPU is an ATI 6950 2Gb ram - a bit old, I know, but it still runs all of my other games (the whole Crysis series, BF4, Max Payne 3, etc.) extremely well. I will eventually upgrade my whole system, but I am a bit limited with funding at the moment. I originally went with ATI to take advantage of Eyefinity, since I had 3 24" monitors that were non-matching and Nvidia couldn't do that unless the monitors matched. I've since moved to a 39" Samsung LED TV and now only use one 24" monitor on the side for FSRealWXlite. I run FSX in windowed mode on the 39" with a program called Windowed Borderless Gaming which removes the border so it looks like full-screen.
I also use SweetFX in DX10 with the free version of Steve's DX10 fixer. I know that a lot of people don't like, have problems, or don't use, DX 10 preview, but I really, really like the way it renders water. I love those whitecaps! The cockpit shadows (especially with this Carenado Cessna) are some of the little details that help me with the immersion factor and my suspension of disbelief. DX9 does not provide those little details.
I've tweaked the heck out of my version of FSX to the point where it's smooth enough that I am now finally enjoying the flying experience as opposed to constantly looking for just... a... bit... more.
That being said, I can always use some tips on image quality!
Thanks,
E-Buzz