i think my parents 466 does ~45 under light load ( i really forget though)
im pretty sure when i had my C400 it was ~35 idle.
i dont see how your system temp could be 50c though.. unless your computer is in an airtight box :Q
IIRC intel's temp spec for the PPGA celly is 70~80c, so technically your fine.. but seems awful high. you sure you didnt raise the vCore a bit on accident? or maybe youre using a sh!tty hsf & thermal compound?
but then again, if the app is reading your system (ie: the mobo) temp as 50c, the sensors and/or applictaion may be outta wack.