if you are willing to suffer w/two separate volume controls for the times you are doing the home-theatre thing, any preamp w/a tape loop will work - just plug the h-t receivers' outputs into the preamps' tape inputs.
i'd recommend a melos sha-1 preamp, and electrocompaniet amplification. both steals for the sonics, even when new, imo. when purchased used, it's *really* a steal! :>)
melos f/s for $425 on agon:
http://cgi.audiogon.com/cgi-bin/cl.pl?preatube&1015803332
a *steal* on TWO electrocompaniet amps for $1300 the pair:
http://cgi.audiogon.com/cgi-bin/cl.pl?ampstran&1015431268
another decent ec amp deal - one for $800:
http://cgi.audiogon.com/cgi-bin/cl.pl?ampstran&1015949449
doug s.