If someone else is paying the bill (a company) then you get Verizon because they are the best in So. Cal. If you are paying the bill, don't mind a dropped call or two, want less expensive hardware and a somewhat human approach to billing, getting new phones etc. then I recommend TMobile. However, if they don't work in your house then it doesnt matter.
The iPhone is very cool, but I dont know that I would be prepared to depend on it for business. Apple has however done an unbelievable job of creating a product that creates a visceral and emotional reaction from the minute you pick that device up. I consider myself fairly levelheaded when it comes to technology, but I picked that thing up and something in the back of my head said "BUY THIS NOW."