Glad there is no rebate at least. 300GB Maxtors are a couple dollars more at zipzoomfly and include 2nd day shipping. I stopped using WD drives after they seemed to fail more frequently than I would like. I'm now using Maxtor and usually try to get the MaxLine III's which have a 5 year (from manufacture date) warranty, usually only a few dollars more than the DiamondMax (the drives are identical though).
Considering this and only 20GB more, I would spend the extra $8 (which you are going to spend $5 more on shipping at newegg to begin with). Or if it is a new system, there is a later model of the same drive rated for 3GB transfers for another $8 on top of the lower one.