Repair or replace...???
It's not an easy choice. But to drop another $550 into a unit that is 4 years old and already outdated technology? Say you fix it, but then in 1 or 2 years are you going to want to replace it but hesitate because you sunk $550 into it just 1 or 2 years ago?
Ok, another question to ask yourself is do you have the money to go flat panel? If yes, I'd go flat panel. If not, then repair it as that's better than no TV.
I know what you mean by size. I have a 65" Hitachi RPTV that is 6 years old. Love the size of the picture and it's been a great TV. But it has no digital tuner, no HDMI inputs, just one DVI or component combo and an alternate component input. Everything else is all low-def inputs. Do I hate to replace a perfectly good TV? Yeah, but with the high-def tech out there, the TV just can't keep up anymore. Sadly, I cut a deal with my wife. 25 more lbs lost and I can get a Plasma. So I can replace it with a shiny new TV but I have to work for it. Sigh...
You have the better excuse to upgrade immediately. Damn Hitachi was built too well!!