I just noticed, are you trying to install on your Mac? I've never done a ppc install.
But, at any rate. First off, you did an "expert install" if you selected packages individually. Which is great if you know what you want. Maybe not so great for the first time. I do recommend a "default install" of the workstation. You will get a good selection of apps to try. You can always add to it if you want.
KDE is a good desktop. I like it better than Gnome myself. But it is a personal preference thing. Maybe you want to install them both (if you have the room) to try them out.
As I said, to keep it simple for your first install, I would go back to the first disc, and reinstall everything fresh. After it gets to the end of installing all your software it should ask you to setup X (or x-server). It will attempt to automagicly detect your videocard, and ask you which server you want, 3.3.6 or 4.0.2 (if you don't need 3d use xfree4.0.2). Based on your pick it will ask if you want to test. If you try it, it will show a splashscreen and ask if it is ok. If there is any problem, it will kick you out, and tell you to change some settings. You should be able to use pulldown menus to change monitor, videocard, and display resolution. And then you can retest. Most often it's the refresh rate of the monitor that is wrong.
After you get through that, you will be asked if everything is the way you want it, i.e. timezone, printer, xserver, etc. Then it will reboot and things should work.
OOPS!