You could argue that one of the great fallacies of modern consumer dSLR photography has been the ascendance of the UV Filter over the Hood as the first accessory of choice when buying a new lens or camera.
You see, the lens hood not only protects the front of your glass from knocks and scratches, but it also improves image quality by reducing glare and flare, and by increasing contrast and saturation.
UV filters on the other hand may protect the front element of your lens, but they actually can introduce more flare and glare, degrading the quality of your photographs. This happens because you're putting an extra, usually cheaper and inferior, piece of glass on the front of your lens. This extra piece of glass allows light from outside the angle of view to enter the lens, bouncing around and spoiling the look of the image. (Unless of course that's the look you're going for.)
I would lay the blame for this squarely with the camera and lens manufacturers, who refuse to ship lens hoods with their cheaper glass, and then charge extortionate amounts to buy one afterwards. The official lens hood for the Canon 55-250 IS lens, the ET60, is £19.99 - ridiculously expensive for a simple piece of plastic.
We do have a saviour however, eBay. A similar lens hood to the ET60 (a copy) can be had for about a fiver, including delivery, thank goodness for the internet!
Personally I now use lens hoods on my 18-55 and 55-250, and I find it second nature to flick the hoods on and off, but I have to admit that I still have my UV filters firmly screwed to the front of both lenses. Maybe it's a bit hypocritical, but I figure that the hoods will reduce any glare created by the extra glass, and by having both types of protection I'm in a belt and braces type situation!