I've decided I've tested Vista long enough to where I want to go ahead and buy it. My question is whether or not I should get the retail or the OEM version. I'm planning on getting Ultimate, and OEM is far cheaper than retail. I've always bought OEM versions of XP, but is the price difefrence to good to be true with Vista OEM vs Retail. I want to make sure I'll still be able to do upgrades and rebuild my computer every 2 year like I do, and not have licensing problems.