Red Hat publicly said that RH 8 doesn't support mp3 compression out-of-the-box. I'm afraid I haven't investigated how to make it work since RH 7.3 doesn't have that problem.
And, yes. Gedit is like vi, but much more friendly. If you're familiar with vi, editing the XF86-Config-4 file won't trouble you too much.
If you're reinstalling, make sure to hand-pick the packages related to rpmbuild, the make libraries and the kernel-source (just to avoid future hassles).
I strongly encourage you to upgrade your kernel before installing the nvidia drivers (as well as the kernel-source). Use the up2date utility.
Use the source, Tux.