It looks like (with the 328) if you have a dip or a 28 pin chip, you only have 1 VCC, and are limited to 200ma sourcing, but 400ma sinking (proving that you dont do more than any one port or any one pin can handle.) It still looks like you could source 150 and sink another 200, if you are careful.
If you have a 32 pin chip or any non-dip chip, you have 2 VCC pins, and 400ma depending on how you handle the other limits. You could source 300, or sink 300, or source and sink for 350.
I guess its also safe to say that the AVCC pin should be ignored, but it would be nice to know what the heck it is, and why, ...
What gets me, is that the big DIP package is the weakest, but the tiny QFP packages can handle a lot more current. That is the opposite of what I would assume.