I agree with BG above that the Colnago looks to be early-to-mid seventies Super model, and would be made with Columbus SL tubes and would be quite valuable with original Campy components. They look to be Nuovo Record. It is quite large however, larger than the Chesini. Can't really tell condition of the paint, but it does look like it was well used, and not really well maintained. Ragged bar tape, a well worn saddle, missing front tire, dirty rear tire and dingy cables all point to a well used bike that will need some real TLC. Tough to put a dollar amount to this bike because of the lack of close-up pics, but it's a large frame, likely original Campy group, and an early example, so I would venture to say it could fetch around $1000 or so on ebay, less on CL.

The Chesini looks to be in much better condition. They are a more obscure brand than Colnago, thus it would be cheaper, but I hear good things about them. Look's higher end with the chrome chainstays, seat stays and fork, but I can't see the Columbus sticker on it, so no telling what the tubes are, although I'm guessing SL or better. Maybe somebody better versed in Chesini could chime in.

Check to see which size fits you though, because these bikes are very different in that regard...