Does it matter to the artist financially which we buy?
I've tried fairly hard to find the answer to this in the past, and the best I could come up with is "it depends". You really need to know what modern-day recording contracts look like, and people don't seem to like publishing those.
I've seen talk that some record contracts treat digital downloads differently than CDs, paying out lower royalty rates. But then I've also seen talk that some contracts still make a 25% "packaging deduction" from downloads like they do from CDs, even though there is no packaging for digital bits. Maybe the lower download royalty rates only exist in contracts where the packaging deduction is removed, with the idea being to keep the same "per album" amount paid to the artist between CD and download?
Overall, I think it probably doesn't matter much for signed bands, as the difference in what the artist sees will be small, particularly since I get the feeling that these days most underground artists don't expect to make much money from album sales anyway.
However, on theoretical basis, iTunes *should* provide more money to the artist+label combination, simply because there minimal packaging and distribution expense. So if artists see less money from downloads, it's only because the contract is stupid, and in that case the label is probably getting *more* money.
This is proven when you look at label-less artists, where iTunes wins. In
this writeup, the author reports that his band nets $6.37 per iTunes sale, $4.50 per CDBaby CD, and $4 per brick-and-mortar CD.
That might tip you towards downloads, because even if your money isn't all going directly to the artist, you would still probably prefer it going to the people at the label than to the plastic manufacturers and truck drivers, right?
Neil