I wear a half helmet 99% of the time. Tooling around locally is fine but when I make my longer treks the straps near the ears make some loud wind noise. I finally popped in a set of ear plugs and it was totally awesome! I can still hear my scooter, my buddy's HD, and traffic but there are no more ringing ears at the end of the ride! I'm sure this is old news for you motorcycle veterans but I thought I'd pass the tip on to other less experienced riders.

Ear plugs actually make it easier to hear things in loud conditions. The high-pitch sounds of rushing air make it almost impossible to hear other more important sounds. Though I don't wear plugs when I wear my half-helmet, I do put the straps of my goggles over my ears. At work, ear plugs are always in.

The other day I ordered some motorcycle-specific earplugs that are hollowed out as well. When they arrive, I can comment on their effectiveness.

Been using the earplugs since 1969 when I started flying helicopters in Army flight school.  If you think riding bikes is noisy you should try flying in a helicopter with the doors removed.  The blades beating the **** out of the air at near supersonic speeds at the tip of the blades, a huge transmission right behind you whining like crazy, a turbine engine right behind the trans, and the wind blowing through at 150 mph while dodging trees, animals, etc with just 3' between you and the dirt.  It's one heck of a ride and there is NOISE.  
It's one job where you can get paid to be an adrenalin junky !
It's the most fun you can have with clothes on.

I like the foam plugs; just roll them in your fingers a bit, put them in your ears and they expand to make a good seal.  
And yep, they cut the level of trash noise so you can more easily hear those things you want and NEED to hear to keep your body safe.

There is GOOD REASON that pilots use them.