I don't think there is a problem with Gnome, its just that there is a focus on KDE. There is great anticipation around here for the release of KDE 4.

I am running a lab rat with 256MB of memory and on-board intel video. It's a celeron with a slower chip than in your wife's machine. Right now, I have opensuse 11 RC1 installed. I even put on the unstable version of KDE. It does not run well enough for everyday use. Also, there are no desktop effects with this old intel video.

However, it ran well with 10.3 and the stable version of KDE. In fact, it was "ok" with KDE 4, "stable" version and RC1. I have no idea how gnome will run for you, but it will likely work well even on your wife's machine.

The opensuse community updates apps pretty quickly. And there are repos that will keep you on the bleeding edge, if that's what you want. I've been using FF Beta5 since the second day it was out. Each of the previous betas came out pretty fast as well.

I think, as you get used to suse, you will like it very much.