I feel like it's time to start from scratch with Windows 7, I feel like I probably have a bunch of crap in the registry and old drivers hanging around. I was wondering if I'm going to do this is it sufficient to just reinstall over my current Windows or do I need to use a program like DBAN to nuke my HDD first?
I think you're safe with just reinstalling Windows. Just use the custom install option to format your drives before you install, this will delete the access directory for the files. It won't be completely clean, as if you were to write over every bit of data with zeroes like I think you are referring to by "nuke"ing it, but I think people mostly do that for security reasons. That doesn't matter since you're using your own hard drive in this case.