Your meter "locking up at 1." is it showing you it's over range. I'll guess you were on the 20V range, and it exceeded that.
Depending on the size of the capacitor and the current you're running the LED strips at, the output voltage will be somewhere between the RMS AC input voltage and 1.4 times the RMS AC input voltage. If that's significantly more than 12V, the LEDs would have a significantly shortened life. Another, and probably more important point to me, the LED's at 12V are far too bright for my taste, and for most of the folks I work with. That looks like sunrise inside the cars, much too toy-like. Here's my bench tests, top is the AC input direct from the transformer, middle is with just the bridge rectifier, and bottom is with the capacitor, a 470uf across the bridge. Top measurement obviously on the AC scale, bottom two on the DC scale. I actually get a bit more than 1.4 with the capacitor, but I believe the transformer is actually putting a bit more than that out. In any case, the point is the capacitor boosts the voltage a bunch, 1.4 is a good number to use.
