I'm about 1" taller than you but with about the same inseam. My road bike is a 56 (Specialized Secteur) but my "commuter" (really a grocery getter and riding on the MUP w/ my wife bike) is a Kona Dew Plus 59cm.
If you're buying off CL, etc. I'd consider 54 or 56 for sure, possibly one size smaller or larger.