I work at a smaller AV store, and we sell LOTS of Hitachi. We sell more of them than the huge big box stores do down the street. The reason being is that we experience their break down rate to be much lower than other TV's that we sell, their features (4:3 expanded mode is especially good when watching anything that is broadcast in 4:3 - waaaaay better than the crappy zoom mode on the Sony's), and the fact that the customers that buy them go home extreamly happy with their purchase. Happy customers = happy salesmen because that means that I don't have a purchase being returned because the customer thinks that the TV is crappy. Have a look at the 50VS810 if you don't mind parting with a few extra $$ from the 50v500. I think that the extra little bit will get you into a really slick TV. Either way, you won't be dissapointed.

Regarding SD television - you will be dissapointed of the quality once you have a taste of what HD looks like (NFL is doing something right with this one). Granted probably 80% of what you are going to be watching won't be HD. Have a look at the sets in the store and ask if the salesman will show you what a SD signal looks like and get him to show you the 4:3 expanded mode and compare against any other set that only has a zoom mode.
Happy Hunting!