I'd like to get a system that will drive four zones of speakers (Bang
& Olufson, and Polk). My sole input is a server with a Xitel device
that sends sound to a TOSLINK cable. I think that I need roughly
100w/ch, and of course I need an optical input. I'd like to keep it
simple, and so have felt that a home theater system is a bit of
overkill.

Is something like an Onkyo 301 Dolby Digital Decoder, or a Dolby
Digital Preamp (e.g., Denon DAP-5500 or B&K Reference 20) in
conjuction with a power amp a reasonable approach?

Should I consider an integrated amp (instead? as a secondary
alternative?)?

Should I just chuck it in and get a home theater system?

Thanks! I really know nothing about amplification systems, but love
my music.