I don't really trust my own judgement, but want to say that I do like the first dress on you! It's a pretty fresh print and an easy sophisticated fit. I don't like it with the black sweater and boots (I'm a low contrast lover), but if you have a bright cropped sweater and sandals, I'd see it as an easy summer dress for almost anything!
Second dress is too long in the bust. If it was taken up at the shoulders, I know I'd like it *better*, but I am still struggling with midi length skirts, so I'm not really a big fan of it.
Third dress fits you well and has a great retro fit-n-flare style, but the print *is* an eyeful. For low contrast me, that sometimes means I avoid wearing something -- like I'm not 'up to it' on most days. . .so if you can handle the print, I'd keep it.