For Guild Wars 2 on the PC, a GameFAQs message board topic titled 'Are you guys getting slow download speeds?' On Steam, it starts with an initial ~2GB download then the game downloads further content from the Guild Wars servers as needed depending on where you are and where you go in the game (or you can force it to download everything [wiki.guildwars.com] if you prefer). The whole game is ~4GB.
Guild Wars 2 Patch Update
And by slow, I mean 1kb/s? 1st one was downloading at max speed off my tethered phone internet (cable is down right now). 2nd one's going slower than molasses.
EDIT: A temporary fix seems to be to download the 32-bit client and run that alongside your current DAT file. The 64-bit client is dead in the water right now. I have everything patched, but the 64-bit exe ain't loading for squat. The 32-bit client loads fine. For now, I'd say DON'T TRY TO FINISH DRAGON STAND with the 32-bit client unless you love last minute pre-boss kill crashes.
EDIT2: Another patch released. Seems to have fixed the issue with the 64-bit client!!