I started with a Lazer Neon ($44) and just upgraded to the Giro Aeon ($250 - only I paid much less).

Why did I buy the more expensive helmet? I liked the colors/design.
Can I tell the difference? Yes, the Giro is much lighter and seem to be all around better quality/construction then the Lazer. The extra holes for ventilation also aide in head scratching.
Did the Lazer do the trick? Yep, really no complaints with the Lazer. I plan on keeping it as a spare/something to wear on bad weather days or to loan to friends.

Honestly, a helmet is a helmet if you ask me. Find one that fits well and looks good. Like I said, I bough the Giro because I liked the color and had money to waste.