Most manufacturers don't disclose weight anymore. On average, steel bikes without racks are around 22-ish lbs. depending on frame size. My Jamis Aurora is lighter than my 520 (but the Aurora doesn't have a rack, it will eventually I'm sure - both have fenders. I use my bikes for leisure and utility.) A mountain bike is often heavier 25 lbs or more to start with on average add a rack and all that jazz and you may top 30lbs or more. Carbon bikes are light as beejeezus (yes that is the scientific classification) and often weigh less than 15 lbs. all tricked out. They are for racing though and not hauling.
"Things look different from the seat of a bike carrying a sleeping bag with a cold beer tucked inside." ~Jim Malusa
2009 Trek 520-Brooks B-17 Special in Antique Brown
2010 Surly Long Haul Trucker-Brooks B-17 Standard in Black
1983 Fuji Espree Single Speed-Brooks B17 British Racing Green