The D700 remains a great camera and could be a great choice for you, but others might want to consider a few things. First, the sensor in that camera was first introduced in 2007 with the D3. The sensor in the D300 dates from the same exact era. Things have changed a bit since then and technology has improved. Pixel size isn't a good measure of quality by itself. If it was, I'd still be using my old D2H. From what I've seen in high ISO D800 raw files that I've processed, I'd much rather be using it than my D700. Second, optimizing your choice around something as inexpensive as hard drive space may not be the best thing to do. 2-3TB drives are dirt cheap, whether used as primary or back-up drives. As for video, I'm not a video fan either, but I'm honing my skills.
As for the D800 users guide, it's stuff we've known for years. I suspect they're just trying to educate people who have little experience with DSLRs or think magic things will happen without considering technique. That doesn't work with either 12MP cameras or 36MP ones. It didn't work well for my 4MP D2H either.
As you might guess, I've decided to move on from the D700 to a D800. I see many things I like in it, despite how much I loved my D700. My son now has my D700 and is thrilled with it. It's an incredible step up from what he had been using, which was a D200. I suspect we'll both be pleased with what we're using.