[masraum]

I'm no expert, but a few notes.

When you increase the range of the zoom to try to make it better at several different things (wide angle/telephoto) you have to make compromises. Generally the zooms that offer that sort of range are considered to be a lower quality. The optical quality has to be compromised to make a lens capable of that sort of range. I suppose it depends on how serious you are.

The convenience and appeal of a one size fits all lens is huge, but at the sacrifice of image quality.

With most DSLR cameras you will have a crop factor, usually 1.5 or 1.6:1. What this means is that with a normal film camera the image behind the lense will be (I think) 24x36mm, but when you go to a DSLR like the XT where the sensor is smaller than a normal film frame you loose some around the edges because the sensor only gets the center of the image.

So, when you think about lenses on a DSLR you must keep in mind that to get the wide end you have to go much wider to get the same field of vision. In other words the lens that comes with the XT is an 18-55 zoom, but the 18 isn't like a fisheye lense, it's got a comparable field of vision of a 28.8mm lens on a film camera. If you want wide angle shots you'll need a really wide angle lens.