Until developers start designing games for the GeForce3 as the minimum spec, I don't see how we're going to see very large strides taken.
Consider this. Only now, in the upcoming DOOM3 and Unreal-engined games, are we finally going to see some games that are designed with the original GeForce as the minimum spec. In other words, only in these games are we finally going to be able to see the use of these video cards to their fullest.
It's going to be another two years, in all liklihood, before any games come out that require DX8 as their minspec. But by then, we'll be crying for the widespread usage of newer features.
Right now, I think the #1 difference we'll notice with games that are designed with the GeForce3 as the minspec will be dynamic environments. We should finally have games with living environments. Models won't just look like strung-together limbs and such, but should actually be able to show off cool effects like flexing muscles and the like. Of course, this is a ways off, but it will be very impressive.