Your headset choice needs to be based on what equipment you are going to fly, how much you will fly, comfort, noise canceling ability, and how much you want to spend. If you plan on flying a lot (twice a week or more) or you can afford it then you probably want to invest in a good headset. If you only fly occasionally, you can save some money and still get a decent headset.
I can comment on the two headsets that I have used, though I suggest that you try several brands before you buy. Call the manufacturers and see if they will give you a loner or two to test.
At the top of the line is the Bose Aviaition Headset X. It is one of the lightest and most comfortable headsets made, and the price reflects it ($1,000). It is active noise canceling and runs on two AA bateries. They advertise that the batteries will last for 40 hours, my experience has shown that they last much longer (I keep the volume at the lowest level though). If you forget to turn it off it turns off automatically after a while (I've had it shut off on my head on several occasions, at the end of a long day when neither the Captain nor I had anything to say for a while). The sound is clear and music sounds great through them, though you will need some sort of adapter to use your ipod (I have the PS Engineering Muse, it works well). That's the one gripe I have with the headset, not built in adapter. Overall you can where it all day long with no discomfort. I have a small head, so no headset hurts me very much, but the Bose is the best I have used by far. I've used the Bose in small piston singles, twins, and two regional jets, and can say that it works well in all. I bought mine through Sporty's with my AOPA credit card and saved 5% immediately. Bose has a finance option as well.
The other headset I used on a regular basis was a David Clark H-10-13.4, which is David Clark's entry level headset. For the price it's a decent headset, though I think there are ANR headsets available from other manufacturers for about the same price and I would be inclined to buy an ANR if I had to buy my first headset again. Anyway, the David Clark does a reasonable job of passive noise attenuation, but it does it by forming a tight seal between the ear cups and your head. If you are going to be flying more than a few hours per day, you will be uncomfortable at the end of the day. Gel earseals and a sheep skin head-pad make this headset more comfortable. I paid $279 for this headset in 2000, I think new prices will be between $289 and $300 today.
Once you find a headset that you like, you might consider purchasing one on eBay. You can get a pretty good deal on one if you know what you are looking for. Personally, I would invest in new earseals and microphone cover on any headset I bought used, these are relatively cheap items though.
Good luck, let us know what you end up buying.
