les mecs beaux-
-Watch out, classic english to french mistake (occurs often with google translate). The adjective in this case goes before the noun. So it should be "Les beaux mecs."
Also, that is very informal. If you say that in the street, people probably won't notice either way, but if you are interested, a more formal way would be "Les beaux garçons" (don't pronounce the ç as a c but as an s. If you say garcons, they may get insulted)