I currently own the Panasonic DMP-BD30 blu-ray player and I really like its blu-ray performance, but I dislike its dvd upconversion, so I decided that I want a good dvd upconversion player for under $100. A few days ago I went to Costco's and saw the DVP-NS72HP and purchased it there. I also went to Sony's website and I did not see the NS72HP listed. I'm wondering if this is the same unit as the DVP-NS77H or a lower model then the NS77H?

Same unit, just with an HDMI cable included.

Yup, not sure if the guts are the same but the chassis, the color, the remote, the manual, etc... are the same.

I returned the 72HP from Costco and got the 77H from Frys for $20 cheaper.

Would I notice any difference in pq if I get a more expensive hdmi cable over the included hdmi cable?

Short answer - no! :D

A lot of us on here use monoprice (an AVS Forum sponsor no less) cables with great success. I think I paid about $5-$7 shipped for my 6-foot HDMI cable. If I ever need another one, I'm heading right back to them.