I'm all about the thick. Happy you included photos as I think most people would think too extreme with 'thick' but apparently most guys still like the thin... I do I guess to me thin looks unnatural... Not to say it is, but from those pics at least it looked like it to me.
Personally I like them in between, so not to thin you can barely see them but not so thick that they take up half of your face. I think that there needs to be some definition to the eyebrow to shake your face however too much could override your facial features and draw too much attention to your brows :) Also I think that natural is better! I don't like the drawn on ones... I use a transparent gel to shape mine so I don't have to put any colour on but so that they don't look all messy :P
thin eyebrows have to be filled.. just like all thin eyebrows are filled in these pics.. so thick eyebrows are obviously better otherwise no one would try to fill them up to give a fuller look.. I might be biased but that's just my opinion..
Thick or medium thickness. It looks more natural in a tamed way especially if it's dark hair. Thin can sometimes look the same way intense makeup looks but sometimes can look nice. All of the examples you have above except the last pic look nice to me.