The 20D has adjustable brightness levels.
I usually shoot with brightness at the lowest level, since I so far have taken most of my images with less ambient light than full daylight.
At highest brightness level, the LCD is bright enough to review the menus in semi-direct sunlight, but I always like to shield the camera with my hands or my body anyway. No problem there.
I also got the "'da Oly Protector" from CCNow.com (yes, it's made for the Olympus, but fits the 20D perfectly) plus a microfiber cloth set, to protect the LCD from inevitable scratches. This doesn't reduce brightness to any degree that I notice, and judging from the marks on the protector, it's already saved me some grief.
If you get the protector, remember to use the sticky strips around all four edges of the protector, and not just top and bottom as instructed. This prevents humidity from your breath, dust and suchlike from getting between the protector and the LCD.