L series glass is supposed to be amazing, but paying the extra money may or may not be worth it for the work you're doing. If you're shooting at ISO 100 in RAW mode and planning on large print output, L glass is probably the way to go. If you're shooting largely for web output, then bear in mind that most users will never see the image above 72 dpi, and it won't matter. Go for IS lenses instead.

I used to shoot a Canon 28-80 lens on my EOS A2 and was never that thrilled with it. I bought a Canon 24-85 ultrasonic when I picked up the D60 and its a FAR superior lens. Hold the two in your hands at the same time and you'll feel it immediately.

If you're trying to follow along this thread but don't know that much about photography, here's the explanation:

Canon makes different types of lenses aimed at different types of photographers. The most expensive lenses are called "L" lenses. The glass is a far better quality and is able to focus an image that has many more lines per inch of resolvable image detail, and given proper film and exposure, is able to be enlarged to a bigger print size. Most digital cameras can't capture that kind of resolution anyway; the CMOS or CCD sensors simply aren't there yet.

IS = Image Stabilization. Canon makes lenses that can counteract the shaking of a photographer's hand. It matters mostly for shots taken at a very long focal length (zoomed really far in), or in low light conditions.

RAW mode is an uncompressed image format. JPG inherently adds "noise" and "artifacts" which can make photographers grumpy.