Thinking solely in terms of playing the game, it has to be Hutson.
That said, my first reaction whenever I get this question, I'm invariably going to say Starr.
Because for me, #15 is (i) reason #1 why I am a Packer fan (the "favorite" criterion); (ii) the second most franchise-defining player (after Hutson) in the team's history; (iii) "5 titles" (most relevant stat to me); and (iv) he's the quintessential "person of character" (after my family, he's the most important person and the person of highest personal character I've ever had the fortune to meet).
So, since "best ... Packer" covers all of the above, and since I don't know anything about Hutson re: (iv), my vote is:
Bryan Bartlett Starr.
And do not be conformed to this world, but be transformed by the renewing of your mind, that you may prove what is that good and acceptable and perfect will of God.
Romans 12:2 (NKJV)