Priit
i understand where you are coming from, i am also up in the air about upgrading but funds are also a bit tight.
Without having a voodoo 3 it is difficult to say what preformance gain would be achieved. I haven't read Anand's super7 article, (i had a quick look and the only one i could find was written in 1999), however Anand and many other sites use FPS games such as quake, q2, q3 etc as the scale very nicely as you increase cpu power and also vary the resolution. We have to remember that not this benchmark doesn't nessacery relect what happens in all games. (look at a flight sim, such as MS flight simulator 2000, this game is cpu limited, every video card will preform approximately the same untill the become the limiting factor).
Super7 systems tend to run very well with voodoo based cards (basically voodoo2 and 3), when running games like quake, but i have to admit i haven't seen benchmarks of racing simulators such as need for speed5 (pu).
I definately agree that driver optimisation etc make a huge difference in preformance, and are also very important. The only concern with super7 and geforce2-MX cards (and other agp cards) is whether the motherboard can supply enough current to the video card.