BTW... since you're inquiring about a Blu-Ray burner, and are talking about using Photoshop and Premiere, I have to ask... doing much (few hundred "running time" minutes a year...) Blu-Ray encoding? If so & you can stand the wait, Haswell will be a much better
option. But if you're in need now, the 3770k will give you the best price to performance ratio, and if you're only encoding a few dozen minutes a year, then the 3570k is a great option as well.
One other option is to step up now to the semi-pro level with an LGA-2011 board & i7-3930K 6-core/12-thread processor, especially if you're regularly encoding Blu-Ray video's over 15 minutes in length. Premiere Pro CS5 & later really loves those extra threads. This setup also gives you the potential of a future upgrade to Ivy-Bridge E in October of next year.
You hear right about nVidia Vs ATI, however the difference may be negligible depending on which version of Photoshop / Premiere you use. Also, GPU acceleration in Photoshop / Premiere only works in-program, i.e. effects, transitions, in-program previews, etc... which can be a nice time-saver, but sadly, all encoding tasks are still handled solely by the CPU.
I just purchased an OEM 3-pack of Windows 7 Pro so that I won't have to mess with Windows 8. Windows 8 is fine for touchscreen use, but come-on... to launch into the "desktop" upon startup, you have to install a 3rd party program... really Microsoft... WTF??? It takes a good while to get accustomed to it, but even after more than 6 months, I still think it's simultaneously their best and worst OS ever. Performance wise, it's faster overall than Windows 7, but not blazingly so. As far as an intuitive interface for a desktop PC, it's the worst thing I've ever seen... took me 3 hours the first day to figure out how to shut down the PC & I only found it by accident, I've also had several problems with the Release Preview & SSD's that didn't exist in previous beta versions