Black and LCD has not gotten to the point where they can be stated in the same sentence...
Well it really depends on the set. Saying that blacks are great on LCD in general is not true. Blacks are good on some (very few) LCDs. Still not perfect black in completely dark rooms though. So far it seems that out of all the new technologies, only SXRD can produce a totally black black. Only at a very strict viewing angle though.
The perfect TV just doesn't exist yet. There is always a trade-off. Maybe SED will fix things, LED LCDs will probably fix things before though.