Both energy and China are the big risks. It'll be interesting to see how much of their foreign reserves were used up in January.
To some extent, it is easier for the Chinese to defend the on-shore yuan market (CNY) through capital controls. It is harder to defend in the off-shore yuan market (CNH). Great discussion from a few days ago here: https://news.ycombinator.com/item?id=11008872
I personally have tremendous admiration and respect for managers of the Chinese economy and I think betting against the Chinese government is just a money-losing, dumb idea.
IMHO, the big threat continues to be oil. Cheap dollar funding has pumped up global supply to well past demand. This is crushing the economies of oil-exporting nations through currency devaluation. Ruble, CAD$, Nigerian Naira, Krone, Bolivar, etc. have gotten crushed.
Developed Market banks and investors have poured a lot of money in emerging markets in the past decade. Some of that investment is going to be lost.
It is an open question whether we are working up to an event that is similar to the 1997 Asian financial crisis, 1998 Russian default, the 2012 European debt crisis, the 2008 Global financial crisis, or something milder, or something much worse.