When selecting a helmet, the ones with a 6 point suspension (three straps running across the top of your head, anchored on each end) tend to be more comfortable and provide better protection than the cheaper 4 point suspension (2 straps). However, any properly rated helmet is better than none. Pick one that is comfortable enough that you will actually wear it.
I've been around a few people who have had significant head injuries. Trust me, you don't want to do that to yourself, or worse, burden your family with dealing with someone with such an injury. A good helmet doesn't guarantee no injury, but it certainly helps.
I have two helmets: one which the ear muffs kept coming off, so I removed them permanently. It's now my hot weather helmet - I use ear plugs when wearing it, since they are much cooler than the ear muffs. The other helmet with the ear muffs is much more convenient when you need to remove and replace the hearing protection, so gets used any time it's not really warm out.
