All I'll add on wb is that hitting the "auto" button in ACR is really useful to help you see how further you might want to tweak the image because I find visualising the colours on the sliders really hard without this aid!
This av/manual meter thing is confusing me....if the pic marc edited is one of yours, you certainly know a thing or two about pointing a camera with the right settings on it! Were you aware of av pre-digital? Sorry if this is teaching you to suck eggs - but you are aware that av (aperture priority) is where you select preferred aperture leaving the camera to set the shutter - and you to override that +/- 2-3 ev depending?
Your cameras have at least 3 built in metering modes; centre weighted, evaluative and "spot" - please note the " marks as on canon's cheaper bodies, it is about a 5% spot rather than the 1% you may be used to. The metering is plenty accurate in the right hands - but there is no reason not to use a manual meter, particularly an incident or spot meter, if you are more comfortable. If you are though, do yourself a favour and dial the camera to m where you can set what you want rather than figure it out on evs! FWIW though, I, and many others I'm sure, leave it in av much of the time with evaluative metering and the odd twiddle of the ev to keep things sweet. It is worth being aware that the increased resolution of digital over film means lenses become defraction limited earlier than they did with film - think in terms of f11 being your tightest aperture - some will say f8.
There is a small degree of relationship between exposure and white balance. you may have seen this article below. You'll see that the histogram is made of 3 channels - and that to get "perfect" colour - you mustn't clip any of them. In practice, as long as your exposure is good, the colour data will be there.http://www.adobe.com/digitalimag/pdfs/phscs2ip_filmtodig.pdf