Need a new sata hd

[SEAL62505]

I am in the market for a new sata hard drive. I haven't bought an hd for a long time (the pc I built a while ago doesn't even have sata). I will be putting it in a dell dimension 9150 and my understanding is that sata II should work with sata I. (I don't know if the dell is sata I or II) The Dell came with a 160gb drive, but I would like to buy one that is 300gb or less. Any recommendations? 8mb or 16mb cache? I would probably end up putting the OS on the new drive because I would assume whatever I buy is probably better than what dell uses? What makes the wd raptors so pricey? Are they faster just because of the rpm?

Thanks for the info in advance!

 

[jwhitt]

yeah they are faster in use though what id recomend is keeping both drives i thik your dell has 2 sata ports on the board and id use one drive as a data drive and one as a system drive as for recomendations id go for wd..sata 2 is kinda new yet i havent looked into it much and realy if what ive heard is right theres not too much of an increase in using it bus's are only soo fast