Help: DVI/ DVD, Nad t-534, Sony 3100 ES, Marantz,

Hi: I have a Denon 2900 with warranty to 2008..great player but does not upconvert, I am probably going to sell for 450 and change..and want to get
a player that upconverts. I bought the 2910 and not a big difference in picture quality..so going to return, I have been researching the NAD T 534, Sony ES 3100 (5 year warranty) 400-450 range, and then thinking about Marantz 7600
and Pioneer 59 AVI saw some on Videogon for 600.00 and then 5900 saw one used for 750.
I have a Sony big screen, Onkyo Integra 8.4 receiver, and def tech towers.
thanks