I prefer debates to arguments. Debates have more substance and are usually objective, whereas arguments tend to be to emotionally involved and lacking in intellect.
Basically, in my view, an argument is the equivalent of saying "your mom!" or "That's like the nazi's!"
Whereas a debate is "I prefer libertarianism because it is based on the belief that a free market is the optimal way to enjoy liberty and freedom." (and then someone else debates their opposite or similar opinion)
As far as it being worth having debates over political issues and current political events, I feel it's totally worth it and we should do more of it. Not debating the tough issues is like ignoring the 2 ton elephant sitting in your living room, it doesn't do anyone any good and begins to stink after a while. =)