[rtate]

I am trying to optimize my computer audio setup to get the best possible sound.
 I currently have Win XP but was wondering if switching to Vista or 7 would give me
the ability to improve things....
I have been reading about KS, Asio and Wasapi and the like but I'm not sure what is better 
I also currently use Foobar/Softsqueeze and have been really looking at getting
JRiver Media center.
Music is mostly flac with hopes of getting some hi-rez in the future as well...

Suggestions??? Opinions???

[WGH]

Vista with WASAPI sounds better than XP because the legacy KMixer is gone plus all versions of ASIO sounded slightly different but none sound as good as WASAPI.

So I would go with Widows 7 + WASAPI, that way you don't have to go through days of updates to make Vista stable and secure.

[StevensSound]

I don't have advice for you on Wasapi and your OS, but what D/A are you using?

[rtate]

I have a Grant Fidelity dac-9 and plan on using a Jkeny modded hiface as a transport...

[HAL]

+1 for Windows 7 + WASAPI with either Foobar2000 or JRiver MC. 

[StevensSound]

Sounds good, probably Windows 7 is best, you'll have support that way

[Mike B.]

I use XP. The current crop of operating systems are CPU hogs.

[viggen]

I went from a Windows XP laptop with 1G ram and Intel C2D low voltage processor to a Window 7 desktop with 8G ram and AMD X6 processor.  The desktop with Windows 7 sounds better, and I didn't even have to install any ASIO programs just plug and play.

[wushuliu]

W7

[srb]

Windows 7 and WASAPI.
 
Although JRiver MC actually suggests trying ASIO and WASAPI in that order, I think it is more the case of recommending the driver interface that has the lesser potential for problems or glitches (and support calls), not necessarily for absolute audio quality.  For some reason WASAPI can have some stability issues on some systems, but it has worked perfectly on the several Windows 7 systems that I have used it on.
 
Steve