I second the F3, you can use the non-AI with stop down metering and the AI and AI-S completely normal. Also, you can use these links to convert your non-AI into an AI yourself if you dare:
http://pindelski.org/Photography/2013/02/06/nikkor-ai-conversions-diy/
http://www.chr-breitkopf.de/photo/aiconv.en.html
I'll third that. The F with straight prism is still my favorite, but the F3 is an amazing machine that is usually available for even less money. The meter is less intrusive than most, which I prefer since I mostly ignore it. You do get a bunch of "modern" conveience for the price of a couple of S76 batteries. I just leave mine set for stop down metering all the time since I have a mix of lenses. The screens seem to be a bit better than the old F versions, but I plan to update some of my F screens with F3 glass.
I keep being pulled back to this system. Even though I prefer some lenses in Leica and Pentax, the completeness of lens options and the amazing affordability of most is hard to beat. Plus the F (or F3) just makes me want to go take pictures.