Hard Drive Specs?

[objecterror]

I was a bit worried at the specs. right now i have a

Western Digital Caviar SE16 WD2500KS 250GB 7200 RPM 16MB Cache SATA 3.0Gb/s

now, since i've gotten it, a tech where i work mentioned that some 720 gig hard drives were selling cheap. i checked newegg and i see them at 400+ not cheap at all, but, aside from the physical size, i noticed that a few other hard drives have different amounts of cache but cost more.
http://www.newegg.com/Product/Product.asp?Item=N82E16822152046

Now, i have no problem with money, since he mentioned a higher storage drive but, what should i be looking for or what are the bigger differences in hard drives. does one need a lot of cache or rpms? what do the RPMS do for performance and the cache as well. please, any information will be greatly appreciated.

 

[reckliss]

ideally for performance you want a 10krpm drive with 16mb cache (less space)
ideally for storage is 7,200rpm 16mb cache and alot of space

 

[objecterror]

Thanks, now, i have the drive mentioned below, can you or anyone else narrow a enclosure for it? iam pretty set as to which internal iam going to get.

 

[reckliss]

an external hdd enclosure?

 

[objecterror]

Yeah, see, i want to turn my existing 250 gig internal drive, into an external drive. i've seen a few but, i honestly don't know where to turn, it uses a SATA cable, red, black tip and small to connect to my motherboard, does that work the same for an enclosure?

 

[reckliss]

so your buying a new 400gb hdd? if so i would stick with western digital and seagate.

This looks like it fits your needs
http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=1785959&CatId=0
its sata to esata or to usb 2.0 supports up to 400gb