Replacing old wood windows

[Andrew Caldieraro]

Hello, I'm looking at a duplex that was built in the 1890's.  Several of the wood windows are rotted.  I'm thinking about leaving the windows that don't show signs of rot, and replacing all of the windows on the front of the building (these all have rot present).  For this type of place, would you recommend replacement vinyl windows? Replacement wood windows?  Or, another option?  Also, how much does your recommended option normally cost with installation?  I don't have a measurement on the windows, but they are probably 2.5' wide and 5' tall, and they are a single sliding window.  Any suggestions would be great!