Just FYI - another partition on your hard drive doesn't mean your data is safe. There are many ways to lose your data, the most popular by far is hard drive failure. That's when you turn on your computer, you hear this clicking noise and get a dos error message along the lines of "no boot partition found" or similar. This means your hard drive has physically broken parts in it - you're not getting any data off it unless you send it off to people who will put on space suits and take it apart and charge you thousands.
Another couple of ways (more common than you might think) to lose data is burglary and fires. Backing up to a separate hard-drive or even an external hard drive in those cases won't help you either unless you brought that external with you.
There are several on-line backup sites -here's a article that reviews a few (I just searched for this real quick so I can't attest to the info, but you can google these services)
http://www.informationweek.com/story/showArticle.jhtml?articleID=198800795
I have my data backed up all over the place, now. My father-in-law has an old server of mine at his house with a old backup of everything. My house was broken into last year (I live in a nice neighborhood btw). They took all our computers, etc - including the extra hard drive that had my more current backup. I was able to get most of my stuff back from the old server, but I lost a lot too.
Now I have an external drive that I bring to work and dump a copy here like once a week or so.
It just all depends on what risk your willing to take. When you think about having a fire or being robbed you may have the attitude of "well, I'll have bigger things to worry about than my data" - but believe me - anything that you don't have to worry about when that happens helps - any little bit helps.
If your house burns down and nobody gets hurt, your data could be the only thing that you can't replace.