Definitely Jericho for the reasons everyone else has stated. He has the knowledge, the vocabulary, the attitude, all the right stuff to make an awesome commentator. He also has that look about him that makes you believe he could be successful at anything. For instance, when he came out on Raw in that suit this past Monday, I thought wow, this guy dresses to impress and for success, as he's done for, in my opinion, his entire career. But put him in a suit at the announce booth, in my mind it looks natural. I think he would be natural and comfortable with it too. I also highly doubt he would be anything like JBL or Tazz, either making jokes all the time-Tazz or overselling the horror of certain matches and moves-JBL. Jericho is, in my opinion, the best candidate for the job.
PDecicco said Raven, I could not agree more. I remember back when he was commentating Sunday Night Heat with, I believe the Coach. I thought he was gold. Granted, he wasn't given the chance he deserved in WWE, his commentating was fantastic. His reasons are similar, knowledge, vocab, and experience. He may not have the "look" of a commentator, but he gives some of the greatest promos because he knows how to tell a story. I also like the idea of Tommy Dreamer, I am not sure why, but I think that would be very interesting commentating. From his blogs, I can tell that he has a lot on his mind about wrestling and other stuff. I think commentating would be a great way for him to connect with fans even more. I could picture him commentating ECW as a rebel type, instead of telling and selling the WWE's version of ECW, he could rip into it and tell the story of the true ECW.
Another guy I have in mind is Stone Cold Steve Austin. Austin is still hugely popular and will always be #1 in my book, after all, he's the one who got me interested in the WWF, Taker's the one who keeps me interested. What he looks in look and perhaps, vocabulary, he certainly makes up for in knowledge, experience, and popularity. But I think Austin because of the way he talks. When he delivers promos or is doing interviews, it was very conversational, it didn't feel like a monologue, it always felt like dialogue. I think commentating, even though there are two guys, sometimes gets to be monologous and I think I made that word up. What I mean is that, for instance, King and Cole, I don't ever feel like they're talking with each other or with the fans. It's more like talking at the other person or talking at us. I think Austin would be very conversational with King, JR, or any of them. I think he would watch the action in the ring and instead of saying, "Randy stalking his prey, and there's the RKO, it's over," he would be more like "Looks like Randy is going for the RKO, King, and there it is, I've never been on the receiving end of that, but you have King, what's it feel like?" Austin could take commentating and make it personal, like two friends discussing a a wrestling match or whatever.