Backup Questions--got The External Drive

I need to learn more about backups. Bottom line is what do I do right now to make sure what I need is saved, because there's some indications that my hardware may be failing. But I want to do it right from the git-go so I don't waste a lot of time redoing things.

A) I have read the 1/26/06 thread started by cway's question--["Originally Posted by cway I am a 'Novice' to Backups, but am trying to learn..."]. It all seems to make sense to me.

B) Now I want to use what Stallcup (in that post) suggests as the 3rd option--["3) You want to avoid having to reinstall WinXP and have the quick, less labor intensive way of frequently backing up programs files and data." namely "frequently clone the system HDD to the backup HDD. In this way, if the system HDD gets corrupted, I can clone the backup HDD back to the system HDD"]

C) I have MAJOR concerns about what Bob Cerelli mentions about having outdated datafiles backed up--["...data has changed since the image was made, you will have old data restored. But a lot depends on how the computer is orgainized. For example, if just the OS and programs are on one partition which is imaged, and data on another, then restoring that first partition it will not affect data."] I have ADD-like memory problems about when I back up what, and I can't afford to overwrite new data with old...

Soooooo...
I'm planning to buy a 200gb external hard drive. Then what?

1) what software do you recommend?
a) Should I use the HP software that came with my computer? or buy something?
b) Ghost? is that Symantec?
(Can someone say more about the concerns with using that software?)
c) Does "ghosting" mean the same thing as "cloning" (in Stallcup's post--#2 above)?

2) how do I know if all my OS and programs are on one partition? (I have an HP and the hard drive is obviously partitioned into "HP_Pavilion (C)" and "HP_Recovery (D)".