I just sold my old backup Canon 10D the other day. I'd have kept it, but needed a backup with liveview.
6MP is plenty to get nice printable images. I've owned most of the popular camera models including the D800. I liked them all. The main issue with the D800 is the difficulty involved in getting that extra resolution that it is capable of. It takes a very careful photographer to do it, and that's not me. Then, you need a powerful computer for any serious post processing, and editing 500 photos is a huge task.
I ended up staying with my 5D MK III, but seriously, any of the DSLR's can capture excellent images, and I'd be happy with any of them if that's what fate dealt me.
Hours before I sold the 10D, I snapped a photo to show the buyer. It was a quick snapshot, but printed nicely at 8 X 10.