I don't think it's too much to say that Sketchup has made my career in many ways. I now do everything in 3d and the quality that it can output has won me lots of jobs. This was from someone who tried Autocad and hated it so did everything by hand very laboriously. I then kept searching on the web like Mike and after trying out lots of 3d software (Archicad, Revit, Allplan, Softplan, Design Workshop...the list goes on!) I didn't find any of them worked intuitively.
One day I came across SketchUp version 1 and downloaded the trial and finally found found something that worked in a commonsense way but frustratingly was only licensed for purchase in the US at the time. I then nagged Tom Wyman at @last and they managed to licence me a copy in the UK and I haven't looked back. Whilst a lot of the original staff like Jim Holman and Tom have left I remain optimistic as those that are working on the software are still committed to improving it. I still keep an eye out for new software but so far, almost 7 years later I still haven't found anything that comes close to its speed and ease of use.
Kenny