Ahhh, the monthly "which headset" thread.
I'm not going to contradict anything anybody's said above (although I use a different type to anything mentioned so far and think that they're great!).
However, if you're about to start your PPL training, use a club headset for a while. You won't get any half decent headset for less than £80 at the very cheapest and could easily spend many times that. Don't do so until you're sure that you are going the course.
G
N.B. Okay, I'll say what I use -
Harry Mendelsson HM40, which is cheaper than anything else, very clear and comfortable, and seems to be compatable with anything (unlike some Dave Clarkes).