There are a lot of people asking this question. Check out this thread too:
http://bikeforums.net/showthread.php?t=288902
Of the three you mention I would choose the Poprad for you. The Cross Check is another good all-around frame. Take a look at the Salsa Cassaroll too.
The carbon fork would probably be ok, but you certainly don't need one. Steel would be the most reliable and comfortable and less of a theft magnate.
If you're commuting most of the time, put some commuting tires on the stock wheels. You can always buy lighter/nicer wheels if you want to try racing in the future. Stock wheels are always heavy and durable and you don't need two sets of heavy wheels.