Screenshots`

[Midnight_LS1]

Make sure your screen is set to a high resolution and that the colour is 32Bit, not 16Bit.
Screen resolution is amongst the most important factors in eliminating jaggies.
Then, also turn on anti-aliasing on your video card.

I noticed you have the 7800GT.  
Did you used to have 6800Ultra before upgrading to the 7800GT?

If so what major differences did you notice?

[Alphajet_Enthusiast]

Indeed I have the 7800, I put it kinda big in my sig too...  ;D
I didnt have the 6800 Ultra before though, however I recently just bought a whole new computer althogether so my graphics and performance improvement has been mindblowing.
But im sure that you could get quite similar pics from Flight Simulator with a 6800, after all the 6800's and 7800's capabilities far exceed the flight simulator upper graphics limits.  :)