Thanks again for all the input everyone.
Sput, I should be at The Glen, I clicked your Facebook link so maybe we will run into each other for the Six Hours weekend. Great photos by the way.
I do tend to do most of my practicing on the race weekends also, constantly shooting, checking, adjusting, trying again.
O2, that's probably a good idea. I do appreciate simplicity (even when it comes to alternately daily driving 3 cars... I remember back when I just had one, and how much more in-tune...each clutch engages in a different spot, each shifter feels different...not that those are hard things to operate, but if I were racing them for example, all those little things could make a difference in the outcomes).
So, I think that I have narrowed things down to exactly the perfect lens for my "one lens, one camera" system:
22-400mm f1.8 stabilized...that weighs 2lbs and is about 6 inches long 
hahahaha.
Usually the 100-400 is all I shoot with at the track (I almost never even mount up the 24-105, because I'm trying to get really tight close-ups of something exciting most of the time). And almost always in the 300-400mm range (practically never at 100mm, for some reason).
Pres, I'll tinker a bit more with the infinity settings. I should really get a better grasp of where exactly infinity is on my chosen lens. I have looked at it in the past, and the lens does have the indicator dial on it, showing you where it's focusing distance wise, roughly. But I do notice that, it has an infinity mark, but you can also set the focus beyond that, and if I am letting the autofocus do it's thing, I notice that even at reasonable distances, the camera seems to select different points around that infinity mark.... so I suppose that maybe "infinity" itself, isn't necessarily a case of "everything further than x-number of feet away", but, like you are suggesting, it's probably usable and good enough.... and who knows exactly what the camera's logic and sensors are doing to calculate differences at and around the infinity mark on the lens. I will give that a try though.
Vracer, I have noticed that too with the ND filters-situation. I do have the budget 50mm f1.8 that Canon sells for approx $100, and while I love the 1.8 short depth-of-field effect, during mid-day, it maxes out my shutter speeds :P (I have a not-very-dark ND filter, Cokin P type I think it's called ? but it's not enough for that lens...maybe if I use that plus my polarizer....hmmmm). That's a good point too.
I would kind of like to have something in the arsenal that would cover the wide-aperture, medium zoom range (might even become a full-time lens if it did really well). something like a 135 or 200mm 2.8 might do the trick, and if I don't need IS, that could probably cut the cost in half too. I do have a friend with a 70-200 f2.8 non-IS L lens, and he said it's great. He shoots college and high school hockey indoors and says it's great.
