Last week my laptop was finally sprung from the basement where it was tethered to the wired internet, held hostage by my new online backup service. When Mozy said the initial backup would take days, they weren’t kidding.
After weighing the pros and cons of various backup methods, I decided to go the online route for a variety of reasons. I was really shopping for two (backing up the household PC and my laptop) and the ease of doing it all online (with the added ability to share files if need be) was a definite attraction. The way I figure it, the price is about the same in the long run and this way it’s off-site, which is a plus. Two less pieces of hardware hanging about is fine by me too.
Mozy came highly recommended and so far, in my brief experience, I find it easy to use. While the initial backup time was laughable, incremental updates have been mere minutes (occasionally longer when I add music) and they haven’t slowed the internet to a sluggish pace the way the first one did.
Now I can finally upgrade to Leopard, which, of course, came out shortly after I purchased my MacBook.
2 Things @ Once 
I have Leopard too! I use Time Machine with an external drive for my backup.