Advice on home systems upgrades

I need some advise on my next step.

Right now, my HTPC is really overkill with AMD 5kBE and 4830. But those were my old main parts before the last upgrade. I've set up a EXT hardrive on the HTPC that is shared out on our network so the wife can access songs an play videos from there. We rarely play games, other than maybe some family style games like Monopoly and stuff. (We have a Wii and PS3 as well)

I also purchased W7 Home Premium when it was only $50 a few months ago. So I need to know what system I should upgrade to W7. I was thinking the HTPC to give it a better interface for the HTPC. I read though it would need a clean install and not an upgrade. Would the clean install just wipe the XP partition and install? Also, can I use that upgrade to more than one of these machines? Also, how can I go about converting my W7 RC to a full version?

I also have not had much luck setting up a mythbuntu pc on the Dell. I got mybuntu to install and, but all the myth TV wiki and forums I read said I cant use my ATI based TV tuner card. Is there really a need for a Ubuntu PC anywhere in this setup? For what use other that to learn linux?



I have the following setup:

1. Cox Internet / Cable & Phone
2. Wireless N Netgear 625 router
3. Computers -
Computer #1 - Mine - AMD AM2-940 Quad, ATI 4870 1GB, 4GB DDR2 800, 1TB HD running Win7 RC - Lan connection
connected to twin 22" LCD monitors

Computer #2 - HTPC - AMD 5000BE, 3GB ram, Win XP, ATI4830, 500GB w/500GB EXT HD. Wireless G connection,
connected to 42" 1080P LG LCD.

Computer #3 - Son (11) AMD 4000+ Single CPU, Win XP w/2GB Ram & 250GB HD. Wireless N connection
connected to 19" widescreen LCD

Computer #4 - Wife - Dell Laptop 1501, T4200, 2GB ram 120GB HD , Win XP, Wireles G connection.
Computer #5 - Spare#1 - Intel Duo Core 5600, 3GB ram, 250 GB HD, ATI 3850 512M WIn XP
Computer #6 - Spare #2- Dell Desktop P4-2.8, 250GB HD, Onboard Video w/empty AGP port

I have access to two spare 1TB hard drives, 1 spare 500GB hard drive, 1 spare 250 GB hard drive, 1 spare PCIE ATI 3470. I also have access to ATI model 600 TV Tuner card that I've never really used much.