Would like advice on building Multimedia PC

Hi All,
I'm attempting to build a multimedia PC to connect to my home theater.

Here's what I have;

MSI K9N SLI Platinum mobo
AMD Athlon XP 5200+X2
4 Gigs OCZ Platinum Memory
3 - WD SATA HDD (200gig, 200gig, 250gig)
2 - Lite-On IDE DVD-RW
1 - MSI NX7600GS-512 Video Card
Ultra X2 600w Modular Power Supply
Wireless RF Keyboard and Mouse
Home Theater (Samsung HD LCD 50", Yamaha 5.1 Surround amp)

Planning on hooking the PC to the TV via DVI to HDMI changeover cable
Planning on hooking audio from MoBo to Amp via Optical cable

Running a network cable to my router for access, and transferring

All I'm planning on with this system is Movies, Music, some games, and minor Internet usage.

Now for my questions;

Any suggestions on my hardware configuration?

Any suggestions on which Operating System? (I typically use XP Pro in my other computers)

Any suggestions on multimedia software that is easy to use and set up?

Any suggestions would be greatly appreciated.
Thanx,
Doc

 

I cannot comment on the hardware but I think XP Pro is a fine operating system to run any computer. I have not used Vista though so I cannot say if it is better or not.

 

Thank You,
I'm not really sure about a Vista upgrade as of yet...
Too many people I have talked to don't really like it.
But I'll keep it in mind.