I get you're still happy with the Denon, but I'd also suggest you upgrade that receiver first. You will hear a big difference with the NAD (NAD always sounded better then Denon in my opinion), or any of the others mentioned - for CD's and streaming even, much less a new turntable. The phono pre-amp in the Denon is a weak link, not just the power, or age of the whole thing. The Project is a decent table for the money, but I doubt you'd be happy spending more money on a table right now as it probably won't make much difference with that receiver - good in its day, but that was a long time ago.
As for turntables, I own a REGA, but the other ones mentioned are fine also. Just one opinion, but I hope it helps.