I'm on a Virgin Media 10Mbps package, with which I'm very happy on the whole. It is very reliable, and I often get my nominal download speed, and quizzically sometimes higher. I guess it doesn't hurt that if I scan the neighborhood for Wi-Fi routers, I get a lot of BT and Sky SSIDs, suggesting that the contention levels on my node may be low because DSL seems to have won battle for the block.
In any event, the nominal upload speed on my package is 512kbps, making for a 20:1 asymmetry between download and upload. I have a JungleDisk account, and it's a great service, but my quick and dirty calculation is that my music collection, as it stands now, would take 22 days to back up to the cloud.
That's painful enough to convince me not to even try, but perhaps I should, because this situation will only worsen as the asymmetry gap widens. Virgin's new 50Mbps package has an upload of 1.5Mbps, or an asymmetry of 33:1. So the consumer has a vastly enhanced capacity to acquire content, but backing it up via the wonder of cloud storage becomes disproportionately more painful, because the rate at which content can be acquired expands faster and in greater increments than the upload.