I've been shooting with a pair of 7Ds for a couple years now....
Most of the time I use Single Point/Center Point. Since I also use Back Button Focus, I can focus and recompose in either One Shot or AI Servo (never use AI Focus, it's slower). If not using BBF, you can only focus and recompose in One Shot. With BBF, you only have to lift pressure off the button to stop AF, before recomposing. BBF allows me to leave my cameras in AI Servo most of the time, using it for both moving and stationary subjects. I do sometime switch to One Shot with stationary subjects, when I want to focus more carefully and accurately (and to Live View when I want the highest degree of AF accuracy possible, although LV is very slow).
I also just center subjects for the shot, but frame them slightly loosely so I have the option to crop the image later in post production. The 7D has plenty of resolution to allow for that. This is handy when shooting faster moving subjects with Center Point only, when it's just not possible to focus and recompose, but I still don't want everything to end up centered.
Spot Focus is a high precision mode, Single Point only. It's a little slower, so isn't recommended for moving subjects. Thanks to the 7Ds capability with moving subjects, I've used it occasionally with moving subjects successfully, and I know some other shooters have too. I call it a "Birds In Trees" mode... since it's really useful trying to shoot through a tangle of branches, or any other similar situation. Of the special modes on 7D, I find Spot Focus about the most useful after Single Point.
Expansion Points and Zone Focus I find useful for some sports and wildlife situations. I use these a lot less often, usually find they work best when the background is really plain or really distant from the subject, so that the camera won't accidentally refocus on the wrong point. An example, Birds In Flight against the sky, either of these work pretty well. If I'm using Spot Metering, I use Expansion Points. If using Evaluative or another form of metering, or just setting the camera to M, I'll sometimes use Zone Focus. Not often, though. I consider these fairly specialized focus modes.
I virtually never use All Points/Auto AF. Maybe if shooting a landscape with a really small aperture and great depth of field. It can be used with Birds In Flight, against a clear sky or solid overcast. But usually not, I just don't need it and prefer to maintain more control over where the camera focuses.
I use a 5DII, too. It's usually with Single Point/Center Point... and BBF... often in AI Servo even though it's not a great action camera. All the same as 7D, really. I haven't found the 6 hidden "assist" points unique to the 5D/5DII to be much help with moving subjects. Only the center point on 5DII is the faster and more sensitive dual-axis/cross type. (Unllike 7D, where all 19 are dual-axis). It's still not as good tracking movement, though, as 7D.
In the past I've used 50D, 30D, 10D, EOS-3, Elan 7E(EOS-33) a lot, plus some of the other Canon models occasionally. At first I tried various things, including Eye Control on cameras that have them. In the end, I've settled on using Single Point most of the time with all of them. It's just what works best for me.... IMO, there's simply no substitute for the photographer doing his (or her) job and working to keep the point of focus right where they want it. Everything else leaves too much up to chance, that he camera will or won't focus where you want it. Eye Control sounded cool, but never worked well for me. I could get the camera to track my eye just fine, but I guess I tend to look around the viewfinder a lot, at things other than my main point of focus, and ended up missing focus way too much with EC.
One thing I miss... EOS-3 have a Custom Function that links Spot Metering to the active AF point. I found that very handy at times (though you had to dial back from using all 45 points to using only 11 or 13 of them). 1DV had this, too. Only 1D-series DSLRs have this feature now, AFAIK. I wish Canon would provide it on other cams... I might use peripheral points more often, if they did. However, Evaluative Metering does place extra emphasis on the area of the Active AF point, so you get some of the same effect with it... in a more limited way.
7D has that special macro mode, too.... though it's not mentioned in the manual or many places. Canon said something about it in a white paper I think. I mostly use manual focus when shooting macro, so didn't really know about it and haven't experimented with it much. Essentially, with any of the Canon USM macro lenses, if AI Servo is used and focus is relatively close, the camera switches to sampling subject distance 4X as often as usual, to increase accuracy of focus. I suspect this would act as a sort of image stabilization, for the axis of movement closer to or farther from the subject. I don't have the 100L IS, so can't experiment with how this combines with the Hybrid IS to improve AF with macro. Maybe some day I'll test it further.
