Opinion: How would you mount a Media center + Server

Hi,
I want to build a machine where there will be a media center and production server.
My question is wether to install Debian or Windows or both.
Mi idea is to have all my movies and music, connect the PC to the TV to watch films and at the same time have a production server to host my web projects before uploading to online server, and make that machine a router firewall with two network cards.

Here's the Hardware:

MB: Gigabyte GA-8I915PMD
CPU: Intel P4 3.20Ghz
RAM: 3GB DDR2 266Mhz
HD1: 200GB [Seagate ST3200826AS]
HD2: 500GB [Seagate ST3500320AS]

What's your opinion, should I install Debian with windows on a virtual machine; should I install Debian on the 200GB HD and Windows on the 500GB and restart every time I want to switch between the server and media center.

My concern on keeping windows is to make it easier to manage the TV connection and movie and music players with an existing remote controller.

Please advice fellows