This might seem a little bit unorthodox. Some would say "How is Gordon Freeman an awesome character? He doesn't even talk!" To this I will simply reply with a "Fuck you and get out of my house".
Our lord and saviour
Gordon Freeman is me. He shares my joy of smashing crates, my hatred of headcrabs, and my desire to show Alyx my crowbar. I don't mean to say that Half Life 2 is my biography. What I do mean is that Gordon is a blank slate. There is a reason Gordon doesn't talk, and it's not because Valve is too cheap to hire a good voice actor. Every time I play Half Life I superimpose myself onto Gordon. He may not say a word, but I do.
Evidence he does exist
Because of Gordon Freeman, Half Life 2 is the most immersive game I have ever played. I still remember the first time I played through it. I rushed home from school with my new copy and played until 2 am. I'm surprised I didn't bring a crowbar to school the next day.
Gordon Freeman may not have the best personality. Hell, he doesn't have any personality, but he's mine. And that's what matters.