If you're thinking about going somewhere with a low COL, Tim Leffel has a good book called "World's Cheapest Destinations" (where he balances COL with cool things to do).
http://www.worldscheapestdestinations.com/index.htmlI'd also say that after having spent last year abroad in 25 different countries (
http://purplmarsh.wordpress.com) that I was really surprised by how many European countries were cheaper than the U.S. I had real sticker shock when I got back after 1 euro cappuccinos in Greek cafes and fresh 1 euro baguettes in France. That being said, many European countries can be hard to stay in for longer than 3 months thanks to Schengen requirements and the difficulty of getting visas.
Australia is pretty easy to stay in up to a year, though, and Air Asia has frequent great deals between Australia and SE Asia.
Thailand is an obvious choice and has a huge expat community. Malaysia's pretty good, too. You can live luxuriously for very cheap, have fast wifi to manage your business, access to good healthcare, amazing food, etc. However, my husband hated Thailand because of how touristy many parts of the country are. I think it's a tradeoff that the more off the beaten track you go, the cheaper and more unique experiences you might have, but you might have to also deal with less comfort and less access to good healthcare. You have to decide what factors are important to you. I think if we were to choose somewhere in SE Asia, it would probably be Indonesia (not Bali) - very cheap, incredible wildlife, gorgeous scenery with literally hundreds of volcanoes, very friendly people, and a good infrastructure in the big cities for stuff like wifi and healthcare.
I personally find a lot of the food in South America to tend towards the bland side (I was craving bottles of hot sauce after several months in Chile), so it'd be hard for me to imagine staying there long-term. Central America - Costa Rica is probably the easiest and has the best healthcare, but also the most expensive and touristy, so similar tradeoff like I was talking about before. My favorite country in Central America is Guatemala, which I think tends to be really underrated.
You can read all you want about a place, but going there and really experiencing it is going to be a completely different animal. Don't make any year-long decisions about a place before you visit first. Stuff like food is really important to me and the diversity of food that you can find in supermarkets and restaurants was one of the things I missed most about the U.S. while I was abroad.
I would suggest first choosing a region that most appeals to you (SE Asia, Central America, S. America) and then visiting several countries within that region on a preliminary trip to see which you like best. Or you could just wing it and just settle down somewhere once you find somewhere you love - a lot of these countries don't really require much preplanning (it may be easier to find a rental while you're there anyway) and many medium-term people just go for a visa run as needed. Sorry that this post is all over the place, but I think it comes down to what your personal preferences are and what exactly you want to get out of living abroad. After our trip, my husband and I have a much better sense of the places we like, and the next time we do an extended trip we'd like to stay in a place for at least several months at a time, so I think it's awesome you're considering something like this!