Where should I go next?

Hi all, I am relatively new to high end, and am building from the bottom up. Literally. I currently have an old Sony STRDE875, DD & DTS, 5-ch. I am playing through an all - Infinity speaker system, Entra One floorstanders L/R, Entra Center, Entra Two surrounds, and an Entra Sub.
I have started building by purchasing a Monster HTPS-7000ss, which although did extend my soundstage and enhanced imaging, detail, and bass response, has not had all that huge of an effect considering my front end.
I also recently purchased a Pioneer ElitE DV-47ai player, and am very very happy with the video performance (through a Philips 4:3 flatscreen, non-HD) as well as the multichannel performance. The stereo performance i really cannot gauge until i have upgraded my front end, but what i can hear in my system now is nothing short of spectacular (even the girlfriend could hear the diff) after my Sony DVD/CD player. I am running some hgiher-quality front cables that i recieved from a friend in the high-end industry, and am not sure what they are. I have Monster XP for surrounds, and a Transparent MusicWave for the center.

Where do I go next? How should i attack this system? I have been thinking a B&K Ref.50 / Ref 200.7 setup might be great, but am really open to suggestions from more experienced 'philes. I do want to build a system that is flat-out phenomenal for both music and movies, from power and speaker cables and interconnects on up to the speakers, which will probably come last - the Entras were cheap, and apart from an overly strong midbass response, are damn good for the cash - $1600 for the whole set F/Surr/sub.

I will purchase most of my equip off of Audiogon, used, and although i'd like to, cant afford the huge prices of Theta Digital or Levinson etc.

HELP! Where Do I go From Here? Any sugestions are welcome either here or on my email. breitlingdj@yahoo.com

THanks, JonBrown