I recently got the PN51E535 from an open-box store (had 50 hours on it) for about $400 (it has one stuck pixel). It has 1018.1 firmware. Colors are great with the settings provided earlier in this thread.
However, I do have a problem with the black level. It is quite high. In a dimly-lit room at night, blacks are clearly gray and much higher than most good LCD displays I'm used to. Actually, on the whole, the set is very bright - again, brighter than most LCD's I'm used to, strangely enough. I don't mean that whites are clipped or washed out. I mean the overall luminance level is incredibly high and can be hard on the eyes. This can be fixed by running at lower contrast settings (around 50-60 seems right to my eyes) but this (and every other setting) doesn't change the black level at all. So the overall contrast is reduced when doing this and the bad blacks are more noticeable at lower contrast settings (because they are closer to the lower white level).
Is there simply no setting on a plasma like a "backlight" setting on LCD's that is available to turn down overall luminance, *including* the black level?
The so-called "Cell Light" setting seems useless to my eyes as it also just reduces contrast and not black level.
Lots of folks here are praising the black level of this set, so perhaps my particular unity is out of spec, though I can't return it (open-box). Or perhaps I'm just more particular about black level than most (well... I know I am. But it's strange to me that a good IPS LCD, properly calibrated, can easily beat the black levels of this plasma).
I even tried tweaking the panel voltage pots, but the critical one, Yrr, is absent from this set (I guess digitally controlled) so there was no noticeable benefit from reducing Vsc etc.