I went on someone's blog today and noticed that they got the background for their blog on this great site http://thecutestblogontheblock.com/
That's where I got this fantastic butterfly background, which is fantastic because it matches my existing header perfectly. There are some really nice backgrounds on there. It makes me tempted to start another blog just so that I can pick another Gorgeous template!
Check it out if you want to spruce up your blog. It's really easy to do, you just ad through the page elements screen. Add the HTML gadget and then paste in the code. Its great.