I plan to update my system with a blue ray player Pioneer BDP-LX91. Do I need also a power amplifier? If yes, which one is best suited. My TV is a plasma Kuro PDP-5080 (HD)
You need some kind of amp unless you're going to use the TV's speakers, which would seem to be a massive waste of such a capable BDP. In that case you really need an AV amp to take advantage of the multi-channel HD audio.