Best Twitter client for the PC?

So I don't use twitter at all, but I kind of like the idea of being able to monitor and track trends and topics in real time happening in the world. That and I feel a bit left behind that many people are aware of this world am I am outside it.

I remember using some sort of program awhile ago that showed a map of the earth with tweets happening in real time, but what do you all think is the best visual representation of twitter and trends and whatever else?