Here is my lowdown on helmets.
Completely agree with the above posters who say you have to try a helmet on. Then try it on again. Walk around the store with it on. For about 30 min at least. Ignore the funny looks you get from the other patrons.
Under not circumstances buy a helmet that you have not tried on. Its just a crap shoot if you do.
My personal recommendation, and my helmet of choice for the last 8 years or so, is Arai. Hands down they are the best helmet made. Not the SAFEST mind you, but the best. All helmets have to pass a bunch or arcane tests to get DOT certification in this country. Many helmet manufacturers, like Arai, go one step further and get Snell certification as well. So I would say that most all helmets with DOT and Snell certification are roughly as safe as any other that have these same certs.
But when it comes to the quality and fit/finish of a helmet....Arai reigns supreme. I have worn Arai, Shoei, Bieffe, HJC, Fulmer and several other I cant remember. I have also had access to friends helmets that I have always inspected and asked to wear just to see what other brands are like. After 19 years of riding, Arai passes every test.
However, if you do not have an Arai shaped head...well, this means nothing to you. I kinda know what you mean about the Icon. There are several Icons I have really liked and when I tried them on at a local bike shop they all felt instantly uncomfortable. My head just did not fit well in them. But they do make very nice helmets.
I would rank AGV and Shoei right under Arai in terms of quality. The only thing here is that both of these manufacturers make cheaper, budget helmets. Arai really doesnt do this. I think recently they have made a cheaper helmet but it is still fairly expensive and doesnt qualify as a budget helmet. Just a cheaper Arai. Doesnt have a removable liner and stuff like that but it still has the fit and finish Arai is known for.
But before I get to long winded on personal tastes I would like to say again that your helmet choice needs to be tailored for your head. From your description, Icon is not for you.
What you might try doing is calling MotoLiberty, a bike shop close to where I live that gives AWESOME customer service and knows everything there is to know about bike gear. Im sure if you call up and ask to speak to their helmet expert and describe the problem with your current helmet and the pressure points you have they can probably, over the phone, tell you what type of helmet you need to start trying on. Yes, they are that bad ass. (I cant remember his name, but ask to speak to the english bloke that knows Phil Read).
Thats their link, give 'em a call. Cant do any harm and they may be able to help.
Hope some of this rambling helps. Jeeze, now people are gonna think I work for Motoport AND Arai.