In search of some answers..

On a random surf-session, came across this post by Meetu
It's pretty much what I've found myself agonising over for some time now. How do you know when a guy is "the guy"?
So ok, you've been talking and things seem nice. Or better than nice, whatever. But seriously, how do you judge degrees of "niceness"?? Are there some standard questions with right and wrong answers that you can throw at him? Is it enough to have some shared interests and a basic understanding of what the other person is talking about? What about chemistry? How much importance should I attach to it? It's a deal-breaker as far as I'm concerned, the absence of chemistry I mean. Am I wrong? Are my priorities getting mixed up? Hell, what the heck are my priorities anyway? Aarghh.
I used to have a list of "desirable traits" that I felt I'd want my life-partner to have. As I got older and wiser the list changed, got shorter, some stuff got deleted and other stuff got tacked on. But you really cant go around measuring people against lists, it just doesnt work. So we come back to the question, how do we judge? If it were a question of simply finding a nice guy, I'd be married by now. But dammit, you can't marry a guy just coz he's nice!!!
I know this isnt something someone else can decide for me, but I sure wish I knew how to go about it. I've been so scared of taking a potential life-wrecking decision, that I've used every excuse imaginable to avoid reaching that stage where a decision was actually required. But now I'm at a point where sooner or later I will have to say yes or no...And I want to be sure that my decision to marry a particular guy was for the right reasons, whatever they are.
I'm wishing and praying for some guidance here...