Those with long memories will remember that I have been looking for a good circumaural headset ever since my Plantronics 655 headset died.
The Plantronics 655 was never the perfect headset. Its ear cushions were too small and rested on your ears so that they would become uncomfortable after wearing them for a long time. Just about every headset has this problem. I was pleasantly surprised to find that the KOSS SB45 doesn't. Its ear cups are large enough to go all the way around the ears so I bought a pair. I am very pleased with them.
My only complaints are that they exert slightly more pressure on the sides of my head then I'd like and that they don't do whatever magic the Plantronics 655 headset does to let you hear yourself when you're on Skype.
Let me explain, you know how when you wear a headset you can't hear
your own voice very well? The 655s play your own voice back to you so you can hear yourself. Since you can hear yourself you don't feel the need to shout. I'm actually surprised since I thought it was a feature of Skype but it works with the 655s and not the SB45s. It looks like some sort of device level feature. It's really useful and I miss it.
Apart from that the KOSS SB45 headset is very comfortable, has a good mic, good sound, inexpensive and I would recommend it.