As suggested by the title, should fresh grads choose a job of a particular field, and learn and strive all the way to excel in that field? Or should they simply get any jobs offered?

I'll graduate soon. I prefer network/IS/Security development/maintenance rather than software/web development. Should people job-hop with jobs of different fields, and end up knowing things, but not in-depth, in many fields? Or should people only choose jobs of a particular field and strive to be a top-notch player of that field?