McEnroe has already said "6+" although I think that's more than an understatement the way he took Novak apart yesterday (against the fittest man on tour, with immense powers of recovery)
(I think the only one Murray will find difficult to win will be the French, but the other three - with two final appearances already in each - he will hopefully win multiple times)
Llendl was a great clay court player, and now that Murray has 2 majors including Wimbledon, maybe they'll spend more time working on his clay game. I still think Novak and obviously Nadal are way ahead of him on clay, but considering the way his game has improved over the years, I wouldn't put it past him.
Henman was very unlucky imo, for better or worse, he was still a brilliant player (and probably had just as much pressure on him as Murray did). I just don't think Henman was as single minded (in regards to leaving home at 12? years old to live somewhere else to favour his playing style - hmm could it be argued as a serve /volleyer Henman was in the right place anyway? I dunno)
I think Tim was just unlucky to be around in an era that had one of the best grass court players of all time in Pete Sampras. People say Tim wasn't that good, but at his best he was ranked 4th in the world. When has anyone in here ever been the 4th best in the world at anything?!
As for Murray, I am immensely happy for him. Every year he arrives with the expectation of the entire country on his shoulders, and every year he gives his all. His performance yesterday was exceptional, forcing Novak into so many mistakes because Novak knew he had to find the lines more than he would against anyone else. Murray was returning shots he had no right to, and that puts pressure on your opponent to come up with something special.
Now for the next challenges for him - more Slams, and becoming World Number 1. I honestly think he can do both, especially as he has reached his last 4 Slam finals. With Federer's powers finally fading, and Nadal's knees letting him down on everything except clay, we could really be into a new era in tennis with Murray and Djokovic being the dominant forces for the next few years. I think we'll see those two in many many more finals together over the next 3-4 years.