I found a WD 500GB for $34 each on Amazon.
Interestingly enough, the other day these were priced much higher. When I viewed them Tuesday (?) they were listed as $34 which I thought was odd. I thought maybe it was selecting 250GB, so I clicked on that, clicked back, etc... and suddenly the price was higher (maybe 60 something dollars).
I closed the browser, searched again, and sure enough it was again $34 for 500GB, so I purchased two of them.
Anyway, hopefully I get the 500GB. They should arrive tomorrow, so I'll backup the 120GB onto the 500GB, and then re-partition; maybe 250GB each (XP and Ubuntu).
Hopefully the partition is a smooth process.
BTW, I have a duplicator, so duplicating hard drives is simple (providing the destination is larger than the source).