I can't seem to figure out which part of the process is the problem. If someone has any clues as to how to go about triaging the problem, please leave a comment.
When I am transferring something to the Macbook Pro from my Debian box using Konqueror (yep, with its wonderful fish:// protocol), if dashboard is enabled on the MBP, the ssh transfer comes to a halt. The problem goes away as soon as I get dashboard out of the way. The problem is reproducible using the above setup at will.