There really is no such thing as "SATA II", so, I wouldn't use that terminology.
SATA Revision 2.0, "SATA II" was copied and pasted from a web-page of an online-retailer (due to failing eyesight, I try not to type too much), maybe you should notify these retailers that they are using the incorrect terminology.
I didn't know OCZ made hard drives. I should use my IBM hard drive for windows 7, it's pretty kickass.
OCZ SATA II SSD, Yes they have been making these for a while, it's also one of the best and most affordable SSD's on the Market at present in comparison to other manufacturers.
SSDs are bad because they can only be flashed so many times (I hate flash memory, it suffers from the malady of RAM in that it needs a constant supply of power). You can't really beat spinning magnetic platters.
There are advantages and disadvantages for all components. In regard to 'Speed', which is the main factor for upgrade, enquire others of their choice of HDD (Platters) or SSD, many will decide on the latter, so who's to decide which is better ?
Of course life is short! It's supposed to be. But there are a lot of silly individuals who are going around stocking up physical objects: packrats.
Life is not necessarily "supposed" to be short, what Life is "supposed" to be and how long a person will live, is best left for the Omnipotent to know/decide.
Yes, it's best to obtain a new system, rather than salvaging obsolete/outdated equipment like 'IBM 6221-38U INTELLISTATION Z PRO FOR PARTS/REPAIR'/'Commodore 64'.