HELP I need alot of audio advice....

I recently purchased a home theatre systems consisting of PSB Image 5ts, 9c and 2bs. My receiver is a Denon 3802. I am running the hsu vtf-3 sub. The cd player is an Apex 800 which is doubling as cd/dvd player. Occasionally, with the help of a well recorded dvd I get great sound; very realistic; but on the norm the stereo cd's and records (played on a Denon DP-47F) sound like dukie. I need some recommendations for upgrades; cables, separates, speakers, cd player or whatever. I'm in much 2 deep....