What backup solution is right for me?

I have a desktop PC running Windows XP SP2. I have around 100 gigs (and steadily growing) of data that I’d like to back up.

Until now, I’ve been manually copying the data to an external 80gig hard drive. As I’ve outgrown that drive, I thought that it would be a good time to reevaluate my storage strategy.

Here are the options as I understand them:
1. Burn to archival DVD and store offsite (I’d like to avoid this because of the time and expense involved — I also don’t really trust CDs/DVDs).
2. Buy a bigger external drive and install some or other backup utility — hopefully there’s an open source Win32 progam that’d work well.
3. Buy/make an external RAID array. (Is this necessary? I’m not looking for performance, just for reliable data storage. I also have no idea what’s involved in making a RAID array, beyond getting a couple of identical drives).
4. Network storage? Wouldn’t this be prohibitively expensive (not to mention time-consuming)?

Feedback?
Re "Data":

It’s the usual already-compressed digital media stuff: mp3s, jpegs, mpegs. I haven’t found it worth the effort to compress anything.
Follow up:
The pricing on the online storage sites that some of you have suggested is prohibitive; ~ $100/month for 200 gigs (the $15/month is for 2 gigs or so).

You can choose between these solutions:
1. Use an online backup service like Carbonite. But in my opinion it is unsafe and rather expensive compared with the second variant.
2. Purchase 3rd party software like Norton Ghost or Acronis True Image. With this software you can store you data on DVDs (I think it is the best solution in your case). I prefer True Image because it is cheaper than Ghost and it has many advantages over Ghost. Here you can read a discussion about that: http://www.dslreports.com/forum/remark,17375409~days=9999
And here you can see a full list of True Image features: http://www.acronis.com/homecomputing/products/trueimage/