i like a more natural look, some background, just change the background so it doesn't look so kitcheny. considering the look of that hat, some sunny location behind, faded and black and white could look good
i prefer the brightened background and darker vignette (last one). i spent like 1 min on this, obviously if you cared, you could do anything to it. if you know photoshop of course. perhaps getting rid of the fridge/door or replace the entire right side with something a little edgier
but no background isn't good, though if you are going to go with absolutely no background, it should be white and do a hell of a crop job, i cropped it in 5 seconds so I wouldn't use those images. but having the background creates balance to the image