The Smith 5906 is one of the best semiauto pistols they ever made. I have handled and shot one. Excellent gun and you can get used ones for very good prices.
Beretta, CZ, and, Stoeger are all good choices.
Just to clarify, the OP is looking for an ALL STEEL gun. The CZ 75 models come in steel and in aluminum frames. The C75 B and the CZ 75 C models are STEEL framed guns while the D and the P01 are both ALUMINUM framed guns.It has already been said many times in this thread but... CZ.
I love my CZ 75 D Compact (basically the P-01). Very glad I bought it. Will pass it along to my boy once he grows.
+1 on a CZ 75 compact. Love my P-01