Well, in terms of performance a RAID 0 array is nice n' quick and you get a lot of storage, It should be faster in windows than a single drive. However, booting usually takes longer and there is the risk that if one drive fails (it does happen) then you loose all data on both.
There is ofcourse RAID 1 which is also fast (very quick reads) but only has half the storage (as one drive is mirroring the first) and has the same delay booting up. However, with RAID 1 if one drive fails, your data should be safe as an exact copy is on the remaining drive.
So, as you can see, there are advantages and disadvantages. However, there is a limit to how cheap mechanical hard disks can be, they all need platters, casing etc. - so buying 2x 250GB drives will actually cost significantly more than a single 500GB samsung F3. Also, if you bear in mind that a single 160/250/320GB hard disk is a good chunk slower than the speedy Samsung F3 - then getting a single fast drive makes the most sense.