Usually a good idea to keep it under warranty for the number of years you'll need it. One thing is that with the 64-bit tsunami in plain view, be sure you are not going to feel submerged in 1 year.
Bob
O.K. so after reading all the reviews I went with the dell over the hp. Just orderd the 9300 with the 4 year in home extended warranty. The cost was $389 with a $100 rebate, so at 289 over 4 years that comes out to about $72/year. I can still modify the order, my question is simply is it worth getting the warranty all together or just save $300 take the 1 year thats offered with the system, and hope everything will be ok..?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic