I started in digital photography in 2004 with two D70's with very good results. I looked for another body that would give me full frame capture (for use with my Spiratone dupliscope SR slide copying device and my Nikon PB6 bellows attachment) with better low light/higher ISO capabilities. The D700 fit the bill nicely. When I was a wedding photographer for 37 years I really enjoyed my Bronica SQb and SQa 6x6 medium format bodies and lenses for the really big prints I could make and I longed for that ability again. The D800 meets that requirement nicely. The expense is worth it if the results are important to you. I still use my D70's (one is converted to IR photography) since the results are still very good! You have a wonderful choice before you!
"Great things are not done by impulse but by a series of small things brought together." Vincent Van Gogh