Actually we totally ripped out our steam system. The story is that Tullo came a few years back for the annual pre-season service on the boiler and found it was all rusted inside meaning it was leaking. They gave me about a $7k estimate for a new boiler. I then called up Royal Heating who had done great work for a neighbor and asked them for an estimate to rip out the boiler, piping, and radiatiors, install ductwork in the attic and basement, a pair of gas fired furnaces and a pair of air conditioners. Obviously this came in well above $7k, but the price was entirely reasonable because we only have a 2-story house with ample space in the basement and attic for the ductwork and other equipment.
I know that a lot of people prefer radiant heat to forced air, but I grew up with forced air and have no problem with it, especially since we have a built-in humidifier as part of the system. Our radiators were covered in 100 years of paint, took up huge amounts of wall space, were a potential burn hazard to kids, occasionally leaked, and were noisy. I'm happy to see them gone. The furnaces we installed are super efficient (which got us $600 in refunds from the state of NJ) and our heating costs are lower, but not hugely so. This year might be a more marked difference as oil cost are really through the roof. It also helped that we converted to a 2-zone system with programmable thermostats, so we're no longer forced to keep the downstairs warm overnight.