Maximum PC

I have an AMD tri-core CPU coming and intend to set it up as a dedicated TVersity box for the PS3s in the house (and properly enabled DirecTV receivers). The first phase is to simply be able to surf Youtube and the like on the internet. I have the required software for ripping my DVDs and Blu-Rays and would like to start doing that as a second phase, adding a larger capacity drive to the TVersity box. I'm wondering what OS to use to do this. I currently plan on using only 2GB of RAM - as more shouldn't really be required, as I understand it.

I have a copy of Vista Ultimate that is not being used. I also have 2 license of Win7 Home Premium available. I would think 64-bit makes things smoother, and both OS's have 32- and 64-bit discs. But I'm wondering about Windows Media Center differences between the OS's, as well. I don't know that I'd even use Windows Media Center, but if I did, which OS, if any, would be better?

Again, my desire is to be able to surf the web and stream my ripped movies, primarily.

Thanks!

Both versions of Media Center work great but Win7's version has a bit more polish to it.

I actually have Win7 on my desktop and Vista on my laptop and both are setup as PVRs.

As far as 32bit vs 64bit goes you won't notice the difference in Media Center. At least I haven't.

It seems TVersity is a 32-bit app so no real benefit to going 64-bit OS. However, if the PC blossoms into a 'server' with multiple apps I'll have to consider more memory and 64-bit.