No need to post anew! These kinds of forums take a while to generate responses - especially since most of the members have day jobs (not me - I'm retired

You can probably save a few bucks by doing it yourself, but I'd recommend an already built unit if you're going to trust your backups to it.
Short story: I was reformatted and reinstalled the OS on my primary drive - unbeknownst to me my backup drive crashed at the same time (I think it was a stray electrical charge) and I lost 3 years worth of data.
Do you want to risk your data that way? I bought a Western Digital 120 gB external USB drive for $120 from NewEgg and couldn't be happier with it. There are smaller one's available - but with this one I backup up 3 computers - and I have several backups of mine on it also.
You'll need some software to make the backups - and for this you'll have to make a choice of which methods to use when.
Method 1) Backup - will copy your files to another location, but will not preserve their location on the disk (this'll break links and mess with files that boot the system up). There are lot's of freeware options available (SyncBack and Cobian are the best - IMO). If your system crashes you'll have to reinstall all your programs.
Method 2) Image - will create an exact image of your hard drive, with the programs intact. It can restore your system in 20 minutes or less. The drawback is that it copies everything - including the stuff that you don't need - and takes up more space than the backup (since you normally don't backup OS files). You can recover the files inside the image by using a special tool to extract them - not nearly as easy as a backup. I only know of one or two freeware apps for this (but haven't used them). Personally, I use Acronis True Image ($50 US) for this purpose.
Now, I use a combination of the 2 methods to protect my data. I backup the essential files on a daily basis - and I image my entire hard disk once a week. It's a lot of storage but I don't ever want to lose that much data again.
Is it easy? Depends on how technically proficient you are. The Acronis program is one of the easiest that I've used, and I can have my system back up and running within 20 minutes easily (and the new Acronis - v9 - is supposed to have an even faster option). And, once you've set these programs up, they'll automatically do it all for you - all you've gotta do is make sure that they've got a place to store the data.
Hope that this helps!