I swear by the BP. cardigan from Nordies:
http://shop.nordstrom.com/S/bp.....rs/3214495
It's juniors sizing, so select accordingly...It's not v-neck, but it is 3/4 sleeve, comes in lots of colors, lasts forever and is priced well. It's also a good length and so isn't at all boxy, which is the best thing about it.