Thanks for all the helpful information. I decided to go with United.
I realize I need 25,000 miles in a year to qualify for elite status; would these extra trips be worthwhile? Is "creative routing" more expensive? Remember I originally planned on four round trips a year. How much more should I expect to spend to qualify. I noticed that qualifying increases my miles per flight; will I be able to return to 4 trips a year the following year and still qualify?
Also, are there any exceptional benefits to selecting a particular bank or credit card plan? I'll be attending UC Berkeley if location has any impact

Again, thanks for all the help

EDIT: I had some communication problems and ended up purchasing two one way tickets to SFO through United. I only intend to use one of them, but the tickets were nonrefundable and actually cost more to change than to simply buy new tickets. Will I still get the points/miles?