What are your suggestions for a pre-amp?

Accuphase c-200

A sleeper preamp. more flexable than any other pre and will surpass the NAD's you have (by miles) and you can upgrade around it, a bargain used. A revelation to your ears.

Research it..

Since you say "will have" I recommend you put together differentially a balanced system. Something like the PS Audio GCC series and a Raysonic 168 CD player. The 168 has a fantastic variable tube outs, so you can just get an amp. But, if you want to incorporate HT then get the GCC

Another good-sounding alternative is the Audible Illusions Modulus series of preamps. Often seen here from $700-900 or so. I agree that tubes add that certain something. If you like vinyl, the John Curl phono board (an option in later Modulus pre's) is very nice sounding.

I like octal tube amps, so the Mapletree Audio amps are just so musical to me. The Ultra4 SE is about $900 new, but rarely seen here used. You'd have to ask Dr.Lloyd to add a sub output for you, should cost you $50 additional. I saw a deHavilland Ultra-Verve close to your price range, which is another rich, musical octal-tube pre.

The Juicy Music Peach is also pretty nice sounding, and within your budget.

Hope this helps!

I'm an advocate of tubes. To my ears, they sound more realistic than SS.

Manley Shrimp would be at the top of my list. If you need a phono stage and remote, Quicksilver Full Function Preamp would be an excellent choice.