I have bought a "Pro" account with YouSendIt.com, which I like. Simple and useful. I'm especially impressed with the download speeds. I have two different broadband connections for redundancy, and on the fastest one (cable), I get between 2 and 3 MB/sec downloads!
I tested a 100MB file. When I uploaded it, it took exactly 20 minutes. When I downloaded the same file, it took exactly 45 seconds!
That is a huge lopsidedness. I forget, is there a solid technical reason for this, or is it just ISP politics to keep you from using too much bandwidth hosting video from home or whatever?