After reading over some hints on this site, I've noticed that many direct you to open the XML plists (property lists) in a text editor and work from there. I very recently discovered that this is not necessary in many cases.
If you install the Developer Tools, one application that is included is called "PropertyListEditor". If you simply double click on the property list you wish to edit, it should open in ProperyListEditor, and it provides a very simple means for editing your plists. (If it doesn't open, the editor is in /Developer/Applications)
One help article I read on this site described how to go through the complex (painful) process of removing the preview from the column view of the Finder windows. I managed to do the same thing, without all the complexities (i.e. I opened the Finder's plist, went down to the column view prefs, and changed the 'Preview' boolean from 'yes' to 'no'. Logged out then in, and VOILA! no preview), and I did it in UNDER 30 SECONDS.
I think that this will have a drastic impact on the way I customize my system, and I hope it makes your world a little easier, too.

