The air is thin enough that I'm pretty sure your blood would boil.
No. This is one of the most widespread misconception about the human body & space. The blood circulatory system is sealed, as long you aren't hurt.
http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/970603.html
You do not explode and your blood does not boil because of the containing effect of your skin and circulatory system. You do not instantly freeze because, although the space environment is typically very cold, heat does not transfer away from a body quickly. Loss of consciousness occurs only after the body has depleted the supply of oxygen in the blood. If your skin is exposed to direct sunlight without any protection from its intense ultraviolet radiation, you can get a very bad sunburn.
The human skin is elastic enough to hold everything in place. Martian gravity is going to help anyway. Eye/mouth/nose protection would be needed, as body fluids would evaporate in such a pressureless environnement. I guess it would be good to protect the ears too. So some kind of big gas mask that cover the ears too should be enough.
Note that during a suit test in a vacuum chamber in 1965', the suit integrity failed and the subject got exposed to near-vacuum. He suffered no permanent injuries.
Now of course, you don't want to get exposed to those conditions for hours, but in pressure contingency cases, you could probably walk to the next habitation module airlock.
---------- Post added at 07:21 PM ---------- Previous post was at 07:06 PM ----------
Obviously a bad idea at -200 C, but the atmosphere would be more than thick enough.
With 1,47 bars, 95% N2 and 4% methane, Titan atmosphere would probably be ok. However, I've no idea how the skin would react to a concentration of 4% of methane in the air. Again, I would protect the eyes and the ears (those don't like pressure variations, as you can feel when you take a plane).
Now the -200°C is of course an issue. You wouldn't immediately turn into a statue of ice (Hollywood movies like that !), but you would certainly be exhausted very quickly as your energy would be drained by the cold. Then the body protects the heart and the brain by closing blood vessels that aren't required for survival : you lose sensitivity in extremities first, then they ice, and you lose consciousness and eventually die when the brain temperature falls under an acceptable level (around 32°C I think).
However, an heating device should be enough like a light suit with electrical resistances in it. You would probably need to carry some fusion cell on your back to power the thing for a long time, though