I have problems with my hearing, partly due to motorsport but mostly from other reasons. With motorsports its something thats happened over time, since there is only one occasion where I've really gone "ouch" at the noise levels, which was stood at the Melbourne Hairpin at Donington in '04 during the FIA GT race.
I choose not to wear ear protection simply because I love the sound, and partly because I've always known I'll still struggle to hear properly weather I've attended a race day or not. Thats probably a bad thing, but I don't feel uncomfortable with the noise - if it started to become uncomfortable then I'd do something about it, because I know I'd be at risk of further damage.
But it confirms the point made by SZRacer - "Being hard of hearing is not particularly cool or manly" - I know this very well, I forever feel like I'm annoying people when I have to ask them to repeat something numerous times. I've lived with it for most of my life and wouldn't wish it upon anyone.
But when a screaming Murcielago R-GT passes by followed by a thundering Corvette C6.R - there's no chance I'll wear any ear plugs! The sound is just too glorious!