Ok so I've just built my new i7 gaming rig and would like to get windows 7-64 bit to get the most out of my memory. (Only own windows xp - 32 bit)
Would it be better if i bought windows vista home premium 64 bit on newegg.ca with a windows 7 upgrade coupon? because I will save a lot of money this way instead of buying the windows 7 home premium 64 bit (full version) when it comes out. Also in the future if i want to reformat my windows 7 home premium 64 bit, am i able to do this with the upgrade version of windows 7 or will i have to reformat using vista and than upgrade to windows 7 from there? (would that leave files that i do not need from vista?).
There is no reason for you to buy Vista and then upgrade to Windows 7.
As you are running XP 32 bit now, you will need to do a clean install of any 64 bit system, there is no way to do an inplace upgrade.
As an owner of Windows XP you are eligible to buy Windows 7 upgrade eddition, it will contain both 32 bit and 64 bit disks in the box.
There is only about 6 weeks to go before Windows 7 hits the shelves, so you may as well wait and buy Windows 7 Home Premium Upgrade.
This way you only have to install once.
Any future reinstalation of Windows 7 upgrade will only require you to have your Windows XP disk and your disk serial key.
So the answer to your question is YES you can use your Windows 7 Upgrade disk to format your drive and reinstall, have the Windows XP disk at hand with the serial key when reinstalling.
Forget Vista go straight to Windows 7, no point in starting to get used to Vista and in a few weeks forget it and get used to Windows 7.