What should my next OS be?

[Shappo]

I've been running Windows XP SP3 32 bit on most of my machines in the past.
Starting to feel a little outdated since technology improves all the time.

I just put together a new rig not long ago, consisting of:
i5 750
MSI P55 GD65
G.Skill Ripjaws Series 4Gb (2x2)
XFX GTS 250 512mb
Seagate Barracuda 320Gb
LITEON DVD Burner
Coolermaster 550w


Could you guy's suggest me a new OS that would be great for my system.

Thanks

(By the way, not too fond on Vista)

 

[saint19]

Win 7 x64....any distribution.

 

[kraken18]

Slackware