Buying a new video card does take some research and planning, but, you must also take into account the rest of your computer hardware. There is no reason to buy a mega powerful video card unless the rest of your computer is also mega powerful. Even if you plan on upgrading the rest of your computer is 6 months, odds are the prices will drop so much over the 6 month period and you will have spent way too much just to get it earlier. If your computer is cpu limited, you will not get much performanceincrease if any just by adding a high end video card, and have to run with lower settings anyway.
I just upgraded myself. I had to, one of my 7900GTX cards go bad in my SLI setup. I bought an ATI HD4870 card to replace the SLI setup with a single card. This is the first ATI card I have bought new ever. When I first installed it, I was horrified to find that my fps was less than half it was using the 7900GTX cards. The default driver settings were all way to high and performance reaaly was unplayable in UT3. Once I found the correct driver adjustmets, I was happily surprised to see I did get a noticable increase in FPS, really great UT3 DM performance now, but only very slight increase in WAR and vCTF performance.
Since I am new to ATI and the catalyst control center, it took some trial and error to get things right. Now I am very happy, but for the first 2 days I was very very pissed off.