I'm a big fan of spot meters, and that's one thing that has kept me away from Canon (he ducks and runs...). They're not the easiest thing to learn but it shouldn't be too bad with digital. I learned with slide film, so it was shoot, take notes, wait a week and see the results. With digital you'll see what you're getting immediately.

A spot meter doesn't lie or get fooled by wierd lighting conditions (which often make great photographs). A spot meter only tells you about one very specific area, so metering on the most important part of a shot and adjusting your exposure to how you want that one specific area to look in the capture will give you very consistent results. I've found that matrix metering (Nikon, anyway) tends to get fooled by bright highlights but is otherwise really good.

An example: If I were shooting a portrait that was strongly backlit without flash, I would meter off the person's face and set the exposure at +1 over that reading (for caucasian skin tone). It wouldn't matter how bright or dim the light in the background was; I'd know that the face would be exposed how I wanted it to be. I don't really know if matrix would give me what I want unless I bracket. The background would probably be blown out but that's the effect I'd want and matrix wouldn't know that. Matrix would give me a different reading depending on how bright the background was or how much background versus subject (which remember is in shadow). A spot meter would give you the same reading regardless.

I don't always use it but it's a really great tool to have once you're familiar with it. It's all about consistency - a spot meter will give you that control where evaluative/matrix may not. You'll have less of a need to bracket and know that you got what you want.