Riding a Mountain Bike in the city I just moved from where there wasn't much of a biking system infrastructure.  There were lots of trails though, so I bought an OK mountain bike ($350).

Now, I've moved to downtown Seattle and everyone bikes.  I'd love to get into it but not sure if a mountain bike is efficient for road-use.

Should I look into a conversion kit?  Should I just get a road bike and have one off-road and one on-road?
I would at least put road tires on your mountain bike - they really improve your efficiency on pavement.

If your commute is urban w/ lots of stops &amp; traffic navigation, the mountain bike handlebar setup can be more maneuverable for tight situations than a road/touring bike. I do miss the maneuverability of my mountain bike since switching to a road bike. A commuter or hybrid bike may be a very good option, with the handlebar &amp; fork designed for more urban situation vs. being tuned for long-haul riding.