I would choose the denon avr5803. the b&k is a fine choice but the denon has some clear advantages.
processing--great chips from analog devices, such as dual hammerhead sharc processers. 16 burr brown d/a converters.
pure direct mode--doubles front and rear d/a converters while turning off all video processing and display for maximum stereo listening.
THX ultra 2--brand new technology over the 10 year old ultra, helps in movie and MUSIC playback.
video conversion--takes all composite, svideo and switches to component at no video loss (100 mhz component switching, 48 in needed to pass 1080i)
plenty of inputs--including denon digital link (when used with denon dvd 9000 passes all information including dvdaudio through a digital cable) also has 5 digital coax ins, including 4 digital coax ext in for a new surround format that is coming out that is all uncompressed digital sound that uses the digital coax ins.
POWER--170x7.....need i say more!!!