Steam heat is the most efficient and healthful heating system available. If you need a change, and want the best system, then opt for an in-floor heating system off your existing boiler. Since concrete will not be required, the cost factor will not be that painful. It would entail removing and replacing the first floor ceiling, but over the years there would be a payback in fuel saved and comfort. Before you say no, at least look into it. Campare it to the cost of baseboard heating and new radiators (they make designer radiators now).