Are you looking at a hybrid or a road/touring bike for commuting and event/charity rides?

With bikes, you generally get what you pay for... up to a point (and that point is different for different people). For example... a hypothetical $600-$700 aluminum road bike with a carbon fiber front fork and Shimano Sora/Tiagara components will be more than satisfactory for commuting, event rides and such.

After that, you run into the law of diminishing returns. You pay more for lighter, better, more blingy components. I'm not knocking aero wheels, Dura-ace components, carbon fiber brifters, $6000 titanium frames, etc. If you've got the money and the passion, buy it, ride it, and have fun. But you do reach a point at which you are shelling out a lot of money for not much gain in performance.

Here's my recommendation... only because I've been thinking about getting a new commuter bike next year, and I've been tossing around ideas. Get a cyclocross bike. These are sturdy bikes with drop handlebars like a road bike and fairly narrow tires.

They're designed for racing on a course that's a combination of road, XC mountain bike, and steeplechase. Riders even have to pick their bikes up and charge up hills and over obstacles. I know, it sounds like more fun than anyone should be legally allowed to have.

Because they're designed to be rugged, they can take just about anything a commute can toss at them. Yet they still have the geometry of a road bike. So they're perfect for a commute or a charity/event ride.

The downside? An entry-level cross bike is even more expensive than an entry-level Trek road bike.