OEM Windows 7 or Full edition?

So the parts for my very first PC build started to arrive today (http://uk.pcpartpicker.com/p/270yi) but I put off buying the OEM Windows 8 in favour of trying to transfer my Windows 7 OEM currently installed on my old computer. Realising that it's beyond my skill, as I don't even know if that's legal, I'm left with two choices: Buy a new OEM version (£60-70) or a full edition (£130-140) and I just don't know which one is best to suit me, any advice?

So as I understand it, the OEM means that the product key is good for a one time install on one machine, but the full edition can be installed on any machine as long as it is only running on one machine at a time? I guess that is specifically for people who upgrade their PC's multiple times in the life of an OS, tranfering to a new PC with the same OS at least twice in order to get the financial benefit? While the OEM is better for that one of install on a machine that is meant to last for a lot longer?

I'm just not sure if I get it, any advice for this moron would be greatly appreciated.

Strictly speaking, OEM is supposed to be tied to a single machine (though, you should be able to re-install it multiple times on that same machine so long as you don't upgrade the motherboard).  However, physically speaking there should be nothing stopping you from installing it on a new build.  It'll likely install and activate without any trouble.  The legality of it is questionable (it'd be a civil matter rather than a criminal if I'm not mistaken), but technically Microsoft could take you to court over breaking the terms and services/license agreement.  How likely is that to happen?  Not very.  Matter of fact, I don't think I've ever heard of it happening...  But it's up to you.

It's really just Microsoft's (and software companies in general) way of trying to screw you out of more money.  "You don't really OWN that software, you are just licensing it from us.  So if you want to install it on a different machine, you're gonna need to pay us for another license!  And don't even TRY to change the way it functions!" /rant

Yeah I get that, my issue is that it came pre installed on my PC. It was an off the shelf machine, so I'd have to copy from my old 300gb hd to my new 250SSD (which looks so cool btw). I read there are a couple of ways to do that, like off a flash drive, ect.

I am building it from scratch, so its a new everything, besides monitor and sound system. I might still try and get it across, because it does everything I need it to do, any advice there would be helpful.

I'd still like to know is an OEM is better than the full  edition, or visa versa.

Yeah, you can mirror your hard drive over.  Plenty of free tools out there that can handle it...  but since you will be dealing with completely new hardware, it's likely going to be a bit buggy, and may be a pain in the ass to suss out.  There's a reason why clean installs are usually suggested when doing significant upgrades.  As far as OEM vs Full, there's no difference what so ever as far as the functionality goes.  Windows Pro OEM will be identical to Windows Pro Full.  The only difference is in the license agreement.