What Angie said. But I'll also add that perhaps, Alana, it is better to think about this in terms of a continuum rather than two extremes with nothing in the middle, you know? They are not mutually exclusive and you don't have to categorize anything as one or the other. I would say both of your examples in the first post combine some aspects of arty and angular. So, for example, while I love rounded, arty, voluminous draping, I also prefer to have some shoulder strucutre in my draped garments. Therefore I don't tend to prefer things like dropped shoulders or extreme cocoon shapes. This is because I don't have naturally strong or broad shoulders, so I prefer to have some structure there to avoid looking like Quasimodo.
Regarding body type, super structured, angular drape like Angie wears does not work on someone shaped like me. The curves of my body fight with the straight lines on the garment and tend to distort them so they don't look right. The only way around this is to size way up on the angular garment so that it falls straight over my widest part (hips), which then makes me look enormous. Also, something that looks angular on Angie (for example, her silk shirtdress) would actually look rounded on me, because the soft fabric will fall and conform differently on our bodies. If I wanted a really angular look in a shirtdress, I would HAVE to get one in a stiff, crisp cotton, and then I run into the problem I mentioned above, where it makes me look like an enormous block the width of my hips all the way down.
Others have mentioned above that being tall helps with wearing arty or voluminous drape. I'll just say here that I am 5'3.5". Yes, a lot Eileen Fisher swallows me up, but other brands (say, allsaints) are cut shorter and are fine. I do have a very long leg line though, which I have to admit does help a great deal. Shannon is shorter than me and wears EF and other similarly arty styles very well though!