Give it about 10 seconds and see if it's still at 600. I've noticed when the DL starts, and it's connecting, it'll say it's around that, but once it's going, it slows down. I think it's checking the first 60% of the files, which are the base files .
If You see "Steam is having trouble connecting to the Steam servers." or "This game is not available at this moment, try again later", this could mean that the gcf distribution server has died. To be able to log into steam and play You need to remove the steam.cfg.
I deleted the steam.cfg now everytime I "try" to load steam my whole computer freezes up YOU BROKE MY STEAM KYLEGAR
i was foolish and distracted enough to uninstall my steam folder without a backup to "fix that problem" steam deleted 250 gigs of perfectly fine installers, recovering data since yesterday...