Between those two I would go for the Panny. Panasonic seems to have better ratings overall than LG.
I don't know what price you have found, but the Panasonic VIERA G10 Series TC-P42G10 42-Inch 1080p Plasma HDTV from amazon (
http://www.amazon.com/Panasonic-VIER...9291450&sr=8-1) would be a better choice, imo.