Well... my body inspiration is Marilyn Monroe. I have a similar skeletal structure, so I should be trying to get around her weight (adjusted for the fact that I'm several inches taller than she was and more muscular), and some of the clothes she wore would look very flattering on me after I get to my ideal size. But I have very different coloration and a different face shape, so I'd only take it so far.
My limit to celebrity looks is they're everywhere, and sometimes you spot a style on one that has your face shape/coloration/body type and think 'Hey, that would suit me too'. It gets to be a problem when people see their favorite celebrity, who looks nothing like them, and do what they're doing because they're doing it.