I've been thinking of upgrading my receiver and have been looking at some of the 2-4 year old Flagship models on E-bay/ Craigslist such as the Yamaha RX-Z9, Denon Avr-5803, Pioneer VSX-59txi. My present AVR is a Yamaha RX-V2500. Also in the near future I will likely be purchasing a 1080P Plasma and Blu-ray player.

Would it be worth it to pick one of these up if I could get a decent price or would I be better off running separate amps from the RX-V2500's pre-outs? Also how vital are the HDMI hookups. I'm very new to the latest home theater connections/ formats.

Any first hand accounts of the above receivers appreciated

Thanks in advance.