wetransfer for under 2gb, filemail for up to 20gb.
both are FREE and require NO account (ala dropbox/megaupload) to use.
filemail has a limit of "two uploads per day" with the free version, but that's it.
use WT *all* the time, and when those "technical difficulties" pop up, I just use filemail, and 8 hours later WT is working just fine again. (guessing they're doing maintenance sans announcement when it happens)