Jackietools :
Same here, I'm retired and don't really need to but as a hobby like to build a new PC every couple of years. Also I want an unlocked CPU this time and Im thinking I might as well go for the hype rthreading with the i7. That should be good for 5 years at least. Only thing holding me back is the reinstall. I don't have a Win 8 disc other than the upgrade disc. Can I still do a reinstall with that?
Having an unlocked CPU is a big deal IMO. Being able to get another 10-15% out of you PC (Which is the usual jump it seems between Intel CPU iterations) without physical upgrades is totally worth the extra price for the part. I personally love building computers as well, it's fun, it's a challenge sometimes especially when you are trying to troubleshoot problems, and seeing the PC all put together and working flawlessly is a huge reward
You could do an upgrade now, up to an Ivy Bridge unlocked i7, you wouldn't have to change motherboard or installation, and you would get years out of that part, especially with the ability to overclock.
As far as the upgrade disk goes, as far as I'm aware they are only able to be used as an upgrade. You could reinstall your old windows and then upgrade, but that is quite time consuming I think. There may be some work arounds for it on the web, but not totally sure if I'm allowed to post them because of issues MS might have with them. If you do decide to go that route, just Google your question (how to clean install with Win 8 upgrade disk or something like that) and you should be able to find some information on how and if it is something you feel you could comfortably tackle.