Perhaps not as good a buy per/GB as some of the recent larger Seagate drives being offered, but this particular model has the highest reliability rating I have seen -- normally about a 91% excellent-to-good user rating.
Personally, 250 gigs is about as large as I like to go per drive due to the risk of data loss in a failure. Two 250GB drives usually cost less than one 500GB drive, and if the 500GB drive dies you may lose EVERYTHING. In a non-RAID setup, you cut you odds of total data loss by 50% by using two 250GB drives instead of one 500GB unit...
This WD drive normally goes for around $80 plus $5 shipping. The deal will likely expire 11:59PM TODAY California time (Pacific Standard Time). I have two of these I've been using in a video editing platform for the past four months without any trouble.