What do you want? Size or viewing angle? Impact or brightness? Each has its advantages. I wanted a bigger widescreen picture than a 36" tube could offer, but also wanted to keep the depth reasonable (20" on the Toshiba) and the weight tolerable (120 lbs. on the Toshiba).
I considered the 36" RCA very seriously, but felt the Toshiba was a steal for $1299.
The Panasonic is a nice set, of course. I don't think you can buy it that cheaply however. And, for HD and DVDs, the picture is going to be small. The Toshiba does the "squeeze trick" on widescreen and is breathtaking.
There is no difference in HDMI cables. If you can see the picture without visible dropouts or sparklies, the cable is working at 100%. No other cable will display a better version of that picture. You're simply wrong if you think there is a better digital cable than one that is already working.