Mine would be the Ruger Security/Service/Speed Six revolvers as well as the Smith K-frame M&P Magnums - the Model 13 and 65.
I always liked those mid size .357 Magnums, and I feel that they filled a need that many new models cannot fill. For example, the GP100 and L-frames are too big, and the SP101 and J-frame Magnums are too small. However, the Ruger Six series and the K-frame .357s offer a nice balance of compactness and power.