Cliff Notes version so far:
XBox 360 - Releasing November 2005. Price unknown. All games 16:9 optimized HDTV 720p, 1080i. Digital surround. 4 Wireless controllers. 2 levels of XBox Live (1 free, 1 pay). Detachable 20 GB hard drive. Progressive scan DVD playback. 3 USB ports. Access all content from Windows XP Media Center Edition 2005-based PCs (TV, HDTV, music, video, photos). Backwards compatible with "best selling" XBox games.
PS3 - Release spring 2006. Price rumor $450-460. 1080P HDMI Dual Screen output (as well as all other resolutions). Digital surround. 7 wireless Bluetooth inputs. PSP can be used as a controller. HD slot. Blu-Ray DVD player. 6 USB ports. Memory Stick, SD, CompactFlash slots. Backwards compatible with PS1 & PS2 games.
Revolution - Release spring 2006. Not much info released yet. Nintendo has been stating it will be a truly different way to play games. Price unknown. HD output. Free Wi-Fi service. Wireless controllers. DVD player (with add-on module). SD cards. Backward compatible with all GameCube games. Able to download the entire Nintendo library (NES, Super NES, N64).