A drop bar conversion on a MTB is not the easiest thing to do and it may or may nor work well depending on the geometry of your bike.
An MTB can make a fine bike for general purpose riding with a few, inexpensive modifications. The first is slick tires. You'll have to figure out how fat you want to go but personally I like 26 x 1.5 inch tires for general all purpose riding/commuting. It's what I use on my MTB/drop bar conversion/commuter. YMMV.
The second mod that can really help is a trekking bar. Drops require new shifters/brake levers whereas your existing components will work fine with a trekking bar. They are popular in Europe and frankly they make a lot of sense as they give you xtra hand positions. I use trekking bars on one of my MTBs. I'm a long time road rider and I love my drops. That said, the trekking bars immediately felt comfortable; they're great. Here's a pic of the my bike with 26 x 1.5 inch tires and trekking bars:
