Argentina recognizes dual citizenship... there's many Argentines that have Italian, Spanish, and German citizenship from their parents and grandparents. As long as you're not swearing to renounce all other citizenships, I wouldn't worry about it. And even if you do swear (in other words, LIE to your new nation), the US government doesn't recognize you giving up your citizenship unless you go to a US agent in a foreign country. And now, there's even a fee before you can renounce.

So not easy to do by accident.
That's not to say things won't ever change, but the trend is towards a more transient world with more countries recognizing dual citizenship. I wanted Spanish citizenship, but decided I didn't really want to lie to Spanish authorities to get it - I will always be an American first.
I thought about getting Argentine citizenship, but two things hold me back. One is the tax obligations... right now Argentina is less overbearing than the US when it comes to taxing its citizens abroad, but that could change. I don't want to be in a situation where I'm having to pay taxes to two or three different countries. Secondly is the protection of being a US citizen. I realize that the chances of the Embassy coming to my aid in case of trouble are slim to none (and I'm not looking to get into any trouble), but it's still good to have.
And frankly, I just don't feel Argentine. I've been coming for the past 8 years and married an Argentino and any future children will be Argentinos, but I don't feel it. I have no grand loyalty or love for this country, so it seems more of a citizenship of convenience than actually wanting it. I do agree though, if you're planning on living here for the rest of your days, citizenship is the best path.
It's too bad that temporary or permanent residency is not easier to acquire for the rest of us that are more undecided!
