Gunnery used to be spoiled for me whenever there was a lot of tracer or an explosion onscreen. Every time an aircraft blew up, everything paused and jerked until the smoke dispersed. But now you can lead an attacking fighter with your tracer stream, and watch the tiny explosions on its fuselage as your shells find their target. When it blows, the explosion is handled with ease. It's made a huge difference to the experience.
Falcon looks great.
The subjective experience of flying the helicopter sim was only marginally better with the GeForce 3. The GeForce 3 is clearly an impressive and desirable piece of kit. It shows good results on the latest sims, and it's the future you should be looking to when investing in new hardware. If you've already got a GeForce 2, I would think not. The new board is superior, there's no question of that, but the improvements you'll see today wouldn't justify the outlay.