If you are a newbie in Linux, I recommend that you stick with the default settings for a while. Eventually (soon) you are going to get the hang of the operating system, and then you can start trying out new things.
This probably means:
- Using GNOME at first
- Going with the default panel layouts (menu panel on top, app switching on the bottom)
- default shortcut keys
- launching apps using the menu
- switching apps using the bottom panel
- drag-and-drop just to manage files
Over time, you may try KDE instead of GNOME (or switch to using Kubuntu instead).
You can rearrange your panels -- for example, I've removed the bottom panel and instead use the AWN window manager or Docky (http://do.davebsd.com/wiki/Docky) to switch between apps and start new apps. You can play around with shortcut keys once you figure out which ones don't really work for you or are getting in the way.
In general, I wouldn't rush to customize until a) you've gotten comfortable with the system, and b) you feel you have a need to change things around.