I have always weighed my bikes by standing on the bathroom scale, then standing on it while holding the bike and subtracting.
My Felt commuter road bike comes in about 22 lbs. in stripped down configuration (rack but no bags), and closer to 30 with my usual commuting setup.
Custom-built Marin Pine Mountain utility hauler bike comes in closer to 35 lbs WITHOUT any bags.
Recently re-built 1995 KHS Alite 1000 MTB using spare parts I had in the garage, built up as a rigid gravel-grinder type of bike. I picked up some new 2.0" tires with much less tread in the center that works awesome on paved and gravel roads, but still with some off-road capability. It comes in fairly light at just under 25 lbs but there is room to make it lighter (new stem to replace the heavy adjustable version, narrower bars, smaller bar ends).