Upgrade Advice Needed for entry high end HT system

Many moons ago, I broke up my stereo system into a high-end 2-channel system for my living room, and took what was left for a mix-matched HT system in the family room. A fried monoblock and a mis-performing old Fosgate Model 4 processor has long since reduced me to listening to tv in mono... I'm finally circling back to coming into the 21st century (read: I talked my wife into it) and I'm going to start re-building.

I had a B&K EX 442 dual 200w monoblock 2-channel amp (used to drive my rears in my old system).

I just bought over Ebay a B&K TX4430 200w 3-channel amp. Voila. Done in amplification. Now it gets trickier.

I have a very good center channel speaker, the NHT VS-2 (it was matched to my NHT 3.3s, which are up in my 2-channel listening room, now).

I have a pair of Energy 22.1 bookshelf speakers that in a previous house were purchased for a satellite room for "auxillary listening." They're good speakers -- think they were about $1k when I bought them in 1996ish.

I'm thinking I need to match my front three up a bit better (and not match the NHT center with the Energys). Which goes and which stays? My thinking is the NHT will be far more sellable on the used market, and far cheaper to replace in terms of a center Energy speaker, assuming it's not rocket science matching current Energy center channel speakers to my 22.1s?

Thoughts?

Of course, the solution to the above will guide what I do in the rears.

Then, I'm going to have to get rid of my old Fosgate Model Four 1991 pro-logic processor and get a new DTS processor. I'm a BIG believer in used equipment.

What should be on my short list of used processors? User friendly is a watch-word, since it's not only me that plops down and picks up the remote. What are the key areas in judging a processor these days? What separates a really good one from all the rest? What price point should I begin to prepare to spend to get a late-model quality processor?

Finally, what do I want in a subwoofer? Remember, this is not a music-listening system, only home theater. But, you can already glean that I'm not going to march into Best Buy and pick up the cheapest sub they have. I presume I want something fast and something that will blend effortlessly into the system, something that's not going to drive me out of the room but will also make me say HOLY COW when it's supposed to. This is also an area I'll likely go pre-owned on. About the only thing new that I'll be looking at is when I upgrade my DVD player, but that's a question for another day.

This is going to be fun.