Please recommend for my next upgrade


My upgrade bug bites me again, although I ok with my current system. My current system consist of:

B&W CDM9NT
Rotel RB 1080 power amp
Audible Illusions L1 preamp
Sony BDP350 Bluray player
Maverick Audio TubeMagic DAC
1 Volex 17604 power cord on power amp
Straight wire speaker cable
Other coaxial and RCA cables are just no name ordinary cables
Monster surge protector (not power conditioner)

I think my weakest links are:
Sony player
Maverick Audio DAC
no power conditioner
power cords
interconnects

I know everything plays a role, but given budget constraint of $500, what would you recommend to upgrade first that will give me biggest bang for the buck? I am thinking probably the player and DAC. Any recommendation?
gte357s
The first thing that comes to my mind is the OPPO BDP-83 blue-ray player that sells for $499 retail. Used in Audiogon is around $430.
I agree with Audiolui, but I would save and buy the SE version of the Oppo. It has WAY better audio performance and it looks like you're a 2 channel kinda guy. You could sell both the Sony and DAC to have some extra money towards the Oppo SE.

Next would be interconnects and speaker cable.
Yes, I am asking from the 2 channel perspective. I have another home theater set up with I enjoy blu-ray. Sorry that I didn't make it clear. So, if for 2 channel music, is the Oppo SE up to the standard?