Trouble is, ugly market realities have been wiping up the floor with 3G lately. And those market realities don't seem likely to change. And 802.11b, which we'll get to in my next column, as the midrange answer.
None competes with one another.
3G also suffers, as often explained here, from cruel market economics. In practice, 3G is unlikely to have an impact on, or be impacted by, the others. Bluetooth's model is for very short-range communications, up to maybe 30 feet. No one wants to use a cell phone that has to be within 30 feet of a cellular-style repeater. Bandwidth is an issue, as well.