(Also if we're getting back into the Best Girl Olympics, leaving aside all other considerations, who's the best wife material in the hotel? It's Maria, right?)
All the girls are plenty good-looking to me--some more and some less, some of which I'll discuss below, but I wouldn't kick any of them out of bed. I think by now (end of content for 0.17.2) we have a pretty good picture of who they are and what they're going to be. So with that...
Kali for me, with Moon as runner-up (since Moon is pretty much Kali but Asian and not rich). She's not the best-looking to me--I favor a slimmer build (e.g., Lin, Felicity, Maria)--but I just like her. A little rough at the beginning, but it quickly becomes obvious that's mostly a result of, first, not being used to receiving compliments, and then not knowing how to handle the fact that she likes MC. But she warms up pretty quickly, and the warmth is genuine. Geeky is a big plus. And her "college look" is very cute.
I'd put Lin next, for all the good reasons mentioned by others. But knowing she'd outlive me by centuries would be a bit of a bummer.
Next up, I think, is Maria. Overall I'd probably call her the best-looking of the girls, but kind of one-dimensional. Yes, she's smart, and can be serious, but it does seem everything always comes back to sex. Not entirely a bad thing in the context of the game, but...
Pixel/Android: don't think I could deal with the non-organic issue.
Ashley, Felicity, Emma: Just don't like them that much. Ashley's also a bit too skinny for my preference--Kate's probably right that she was malnourished as a child--but first impressions (for about half of the content for each of them) really hurt all of them. Ashley's crazy, Felicity's a massive bitch, and Emma goes along with her. And Ashley literally rapes MC, with Maria's help and encouragement. Later content does a lot to remedy this--explain why Ashley is as she is, they all (finally) reconcile, etc.--but that's still a lot of bad first impression to overcome.
Autumn is really a wild card, and (IMO) the one where we're most likely to see significant change yet. She doesn't really fit my preferred body type--she's considerably more curvy (though certainly not fat) than I prefer--but she's undeniably a knockout. She's probably, in the abstract, the best "wife material" of the group.