My latest upgrade

Whenever I go into my local shop and they have a rega planet in, it always sounds better than with any of the others that usually end up in the demo system. I am never familiar with the system because it changes every time I go in, but it impresses me that I can hear a positve difference (three + occasions) and identify it as a certain component.
I don't know how it would stack up to something else to the full 1000 you would spend on something used, but I think it would be a safe bet that you could'nt find something close to it for the 500 bones you could get a used one for. For sure you couldn't go wrong with a planet.
One of the reasons I noticed it was the depth and smoothness it had. Rare for a cd player. (unless you spend more). That should mate well with your tubes.
And actually, one of the systems I heard it with was a cr developments romulas, a 50 watt tube integrated, with monitors of some sort. I was impressed.

NAD 514. Resolution is low compared to what I have come to appreciate, but it's sunny disposition was always appreciated. Available used for about $200.

The Bel Canto DAC/Pioneer DVD transport could be a good option. Used $1,000.

One I have never heard, but always heard good things about is the Resolution Audio CD50.

Not that you asked, but if a high resolution CD source is not super important to you, I think your $1,000 budget spent on the NAD 514, Zero autoformers www.zeroimpedance.com between amp and speakers, and Ganymede VCS roller bearings www.ganymusic.com under your source, would produce SERIOUSLY good results.

Rega Planet - we are a lot like the store Basement goes into. We have several other CD players in the same price range as the Planet but the Planet seems to outsell the others quite substantially and ends up in most of the demo systems we put together for the listening rooms. I think it's a serious bargain.

Add some ACME Audio cryo treated power outlets to my last recommendation for even better results and still stay under a $1,000. The NAD has a coaxial output for use with a stand alone DAC down the road.