Hi Joe, I'll give you a bit of my history and advice.
I travelled through Latin America for 6 months on my way to Argentina, where I lived for over a year, half in BA and the other half in Rosario. In the winter I went to northern Brazil and worked my way down the coast back to BA. In the summer, I travelled through southern Argentina, Pantagonia and then Chile before returning to travel through northern Argentina. At that point I had already decided to return to Canada and that's where I am now. The economy is booming and the lifestyle is great. This winter I'll live in Mexico.
Would I recommend Argentina? Yes. It's a beautiful country and one of the easiest Latin American countries to live in. If you have an income of at least $500/month, then I'd say you could live in Argentina quite well. That's based on how I lived though, and I like living cheaply. It's hard-wired into my brain and besides, most Argentines have to live on about this amount and they survive okay. Most have very nice lifestyles from what I saw.
Would I recommend Buenos Aires? No, although that's a marginal no. Visiting the city is always special and the weather is ideal in spring or fall. It's a big city though, and has it's share of big city problems. One of which is that it's still growing out of control much like Mexico city or Rio de Janeiro. It's a nice place to visit but I wouldn't want to live there. The pollution, poverty, noise etc... can wear you down.
My plan was to live in Argentina for a year as if I was making the permanent move. If it went well, I'd stay for 5 years or more. In the end, I decided I was going to leave and not come back. The reasons why are long and some are a bit complicated, such as the way I was treated in Argentina. Very minor stuff on the surface but when people lie to you, to your face, thinking that you're an idiot, it starts to eat at you. The bottom line is that it wasn't the right fit for me and I'm happy to admit it.
It's a great idea for you to visit the country before making any sort of serious decision. The longer the better since there's always a "honeymoon" period when people first arrive and that takes awhile to get past. Even if things don't work out, it'll be a wonderful adventure. Be sure to visit other cities if you can.
Getting money in and out of the country is also a problem and this has been talked about in this forum and others. Doing your banking through ATM's isn't practical in the long-term. It's vital that you're able to set up a bank account and also get a DNI in Argentina. If you don't know what I'm talking about, you REALLY do need to do some homework. A key point is that the rules change when you hit Argentine soil. Applying from your home country can be valuable.
Do you speak Spanish? If not, it's going to be a struggle for you. YES, many argentines speak english (thanks to a glut of english teachers) but long-term life WILL be a struggle if you don't know spanish or have the ability (or interest) to learn quickly.
Another point is that before the crash, BA was one of the most expensive cities in the world to live. This is starting to happen again but in a strange way since the Peso is being held low while hyper-inflation is allowed to erode buying power. The exchange rates and government stats don't tell the real story. I'd rate the whole situation as unstable.
Having said that... Argentina is still a bargin overall compared to living in North America and less expensive that Chile and Brazil in my experience. The cheapest option is Bolivia, just to the north although, living in Bolivia could be pretty hardcore. I found two cities I liked. Sucre and cochabamba (sp?).
Regarding crime, I got robbed a couple times in Argentina and Chile. Both times by people stealing from where my stuff was stored, even when it was locked up. Lots of theft by people who know where to look I suppose. On the street, I'm pretty careful and haven't had that much trouble despite visiting very dangerous areas. One of my major travel abilites is to adapt to my environment though, so half of my contact on the street is from people asking for directions.
Perhaps the most obvious signal of crime is the way every building is built for security with bars on the windows etc... It's not something I'm used to in Canada and I asked Argentines if this was really necessary. Every single one said YES. The bottom line is you have to protect yourself and be aware of that at all times. Just like anywhere in the world I suppose.
That's my general philosophy. I take the precautions & hope for the best - what else can you do?!