Based on your priorities (that you listed above) it would be futile to upgrade speaker wires ,interconnects and surge protectors. The cost of those upgrades will definitely cost you a nice big screen TV. If I didnt have a big screen TV I wouldnt be wasting my hard earned money on things that barely increases the level of listening.
Fortunately I have a nice 78"+ picture from my FP. But if I had that extra money ...

http://www.quadloft.com/hometheater- new HT