I currently have two systems:

System 1 upstairs:
Naim Nait 5i integrated
Naim CD5x
Naim Flatcap 2x
Naim Ariva speakers
(Samsung 42 in HD Plasma)

System 2 downstairs:
Dennon 4800 Reciever
Rega Apollo CD player
Sony 999ES Sacd/DVD player
B&W N805 Fronts
B&W HTM-4 Center
B&W 602 rears
(Sony 50 in HD LCD Rear Projection)

The problem is, I enjoy the upstairs system much more for music than the downstairs system, but I have two children (1 & 2 yrs old) so I am forced to listen to music downstairs the vast majority of the time.

What would be a sensible upgrade to get more out of my downstairs system? I believe the Dennon to be my weak spot.
Or do I move some of the upstairs systems down?

Please advise.

thx