Actually your preamp and amp are not what I would call in the moderate end. Everything's relative of course, but those are excellent pieces and 'for music' you would need to spend approx >$7000 nowadays to get similar performance I would say. This is new of course, you can always find good deals hear on AGON to lower that price.
The only caveat is that for home theater, the Citation 5.0 is a little behind the times. But if you want bare bones dolby digital, it will do fine. Spend some time setting up the bass managment just right and it still will impress.
For music, I would put the Citation's 6-axis against DPL2 any day (and have) and I personally think 6-axis is just as good. This was a music first preamp and was quite pricey when new and there have been no advances for analog music playing that would necessitate replacing the Citation. In fact, with hi-rez formats nowadays, I notice many higher end manufacturers are going back to concentrating on the analog preamp section. But still the analog preamp sections in many pre/pros nowadays don't do anything the Citation 5 already does at least as well or better IMHO.
Your Lexicon was made by Bryston I believe, enough said on that front.
For good speakers modestly priced check out Onix, Rocket and Swan. These are sold internet direct and since you have a low price range these may just let you get some decent performance for the dollar.