As far as a viable colony goes, Mars is clearly the best option in the Solar System. For a first-step base, the moon is the only option. They are different missions, with vastly different needs even after everything is moved. A moon base would not have to be self-sufficient, while a Mars base could much more easily achieve those requirements. A moon base would let us test things in a vacuum and has a relatively small gravity well to climb out of for missions elsewhere in the solar system, while Mars looks a lot like earth from a gravitational perspective. The list goes on... However, I think that in order to be able to send a colony to Mars, you'd have to have at least as many people on the moon first.
EDIT: And currently, Mars is something like 2 light minutes away. At it's greatest distance from Earth, it does take something like 45 minutes for transmissions to go round trip, but that's not the same as .75 light hours away. The distance is half the length of time it takes to "ping" one planet from the other, if you think about it.