My textures look very sludgy, although my system (i guess at least) is fast enogh for beautiful graphics. I have an AMD XP2800+, 512mb DDR-ram and a Radeon 9600SE (ok, the card is not the best, but it´s not the worst as well). I tried changing the graphic options a lot, but i never reach the atmospheric graphics i saw on a lot of pictures about the FS2004. as an example, the horizon should look blurred, if you know what i mean. it should get brighter and brighter and at some point you don´t know if it´s sky or ground you´re lookin at...you can see that very well if you´re flying in real-life. But, in my FS it looks some kind of "cut", the ground ends at an specific point depending on what distance of sight i preset. And the coulors look so sludgy, it´s the opposite of beautiful...

Does the problem actually depends on my Graphic card, or is there any possibility to change that?

There's a option in display/harware/global scenery texture,shoud be set at massive,and MIP quality in 5
  go and hit it the tell me
    cheers

Max anything to do with textures and leave mip-mapping quality at 5

On you ATI card settings, adjust the sliders higher.  Granted the crisper the graphics, the FPS go down.  But you can find a happy medium I am sure.  I am not sure if the sliders are the same as my card, but I have the AA around 4 and the Aneospheric thingy around 8.

Also if you open up the FS9.cfg file, you can edit the parameters under the display settings.  Expand the radius so that the textures appear more clear around you and tapper off in the distance.

In the game I don't set my Mip levels more than 4.  5 and higher do give me a headache also.