Forget Vista, go for the win 7 OEM
Much better on line support, You may not get Telephone support, but you still have access to online support such as KBs
Ex. You goof up and use IDE and want to convert to AHCI. You can still go to Microscoft KB xxxx (Forgot Number) and click on the link "Let MS fix the problem.
MS support (ie updates) is better. I think MS would just prefer that vista would go away.
Only other negative (minor one) is that windows 7 does NOT include a email client.
1) They are tring to move more toward "cloud" computing, ie You can use microsoft Life.
This is even more pronounced with windows 8.
2) They stuck all the email program files in windows 7, But then DISABLED IT. I think the main reason is the legal problems, but also as stated in #1.
.. Alternatives are (A) Microsoft live, (B) 3rd party email programs and (3) what I did for wife's system, ported Vista win mail over to win 7 - Difficault but doable.
Two other distinct advanges of win 7 over both Vista, and XP.
(1) Better support for SSDs, Win 7 has trim cmd, vista/XP do Not.
(2) MS has added a Backup program (in control panel) to alow imaging the C drive, and restoring this image - EXCELLENT program. For Vista and XP need a 3rd party program for this.
Added, Win 9
1) this only delays paying for it
2) This is still Pre release so more than normal first release bugs, may have problems with some drivers.
3) Windows 7 was really a Vista overhaul with a new name, Windows 7. MS had to get rid of the name VISA as Busseniss community would NOT buy. Most Companies skipped Vista and went from XP -> Win 7. Windows 8 is a Major jump, and from what I've read so far is that this may be shuned by the bussiness workld just like ME and Vista.
4) Myself, I downloaded and installed windows 8. Played with it for two days. Removed from computer and trew the DISK in the trash. Only really great thing was increadable boot time, as to the rest of it, well If I wanted a tablet, windows 8 would be OK, O'Hel* I have a tablet and do not need a Hugh NON-PORTABLE tablet!!!