It really depends on length and girth. I was with a guy who was about 7 1/2, but he was so thick I couldn't get him that deep in my throat. Fortunately, his balls were really sensitive, so I was able to get him off by stroking his balls.
I was with an italian guy in NYC when I was in college. He was about 11 inches and pretty thick.
To me they were both monsters. It just depends on the cock.