Download speed is usually what is touted by ISPs. It is usually a higher number. The original thinking behind this was that content existed outside of your house and you needed to download it. Now, to take advantage of "the cloud" ISPs are making the upload speeds the same as download speeds. FIOS has just given free upgrades to their subscribers.
If you are trying to stream Netflix or YouTube, then download speed is important. If you are trying to upload to YouTube, then upload speed is important. If you are trying to use "the cloud" for off-site backup then upload speed is important.