A tech buddy has been telling me good things about SpiderOak online backup and synchronization services. I have them on my list to talk to soon, but I just received notice of a special sale they're running tomorrow, May 20th from 10am-4pm EST: half off. Yes, an “Economic Recovery Special” is a cliché, but also serious savings. You will be hard pressed to find 100GBs of online storage for $5 per month, which is half their already low normal rate of $10 per month. Use the promo code “recovery” for the deal.
Let me know if this works for you, or if you already have a better deal elsewhere. If you want more sales announced this way, let me know and I'll try to persuade other vendors to give us a heads up like SpiderOak.