I have seen some forum posts in big sales forums such as www.salespractice.com where many sales people believe ego is important if you are employed in sales.
In my opinion ego is destructive in selling; the dictionary describes ego as self importance, conceited, opinionated, self importance and vain. Surely this is different than self confidence.
Self confidence is very important in selling, a strong handshake; genuine interest in the customer or client and ability to find out what motivates them.
Many salespeople I have met would be twice as effective if they let go of ego and focused entirely on the customer. It is quite natural for us to be seen by our peers as confident and successful but displaying arrogance and disregard for people is not acceptable in making major sales.