OK, I think I understand a little better now. Let's see: You want more fonts, but don't have either the fonts or the knowledge of how to install them. Right?
Fortunately both of these can be fixed.
As far as I can see, then, your problem is not specifically related to gvim, it's just that gvim is where your lack of fonts bothers you the most.
RHEL3 is beginning to get a little old, but that still shouldn't be a problem. The main thing is that you are most likely using uptodate as your package manager and RH probably doesn't have a lot of font packages on their site. That still should not be a problem.
I have several systems currently running Fedora, which is closely related to RHEL, but just different enough that a couple of the answers I direct you to might turn out to be incorrect for you. I'll give it a try anyway and you can let us know where I lead you astray.
First, there is an entry on fonts in the "Unofficial Fedora FAQ" at http://www.fedorafaq.org/
For the most part, you should be able to use any True-Type fonts. The pointers at the Fedora FAQ to the "Windows Core Fonts" may or may not work directly for you. If they do, that's great -- if not, you should still be OK. You can also find the fonts in rpm form. A site Optimal Use of Fonts on Linux
has links to a number of font packages for several systems and much more information than I am going to try to put into this posting.
You didn't say anything about specific features you are looking for in a font (I'm guessing from the fact that you are talking about gvim that you are especially interested in "monospaced" or "fixed-width" fonts) or about what you find unsatisfactory in whatever fonts you are currently using in gvim. If it's a Courier derivative, I can sympathize.
For a free, open-source, unencumbered font family, I might point you toward DejaVu
(also discussed in the site linked above). DejaVu Sans Mono is, IMHO, a huge improvement over Courier, especially for programming purposes. There are lots of other good monospaced fonts too, but they may be a little harder to find. If you have a better idea of what you are looking for in the way of style or features, just ask and I'll try to point you to something suitable.
As for installing regular (non-rpm) true-type fonts in KDE, this should actually be comparatively painless. This link
should help once you have a ttf downloaded. You may have to log out and back in again after installing to have the newly installed fonts show up in your font list, at least I have had to.
I hope this helps. Keep asking questions if it doesn't get you where you want to be. And remember: Google is your friend!