Maxed out the stock 160GB hard drive
Smooth! I followed iFixit's instructions, with photos, and everything went fine.
Although--I did have to do a little extra research to figure out how to re-route the wires connecting the antennas, to make sure they didn't bind up when I put the frame back together.
Be patient, take your time. I usually don't like working on small electronics but this job was quite do-able. Clearly: I'm using the machine right now!