I'm looking forward to this.
For the GC, here is how I rate the contenders:
Froome - Best team tactically and possibly skill - Froome has some weaknesses but his ability to TT as well as climb has to make him either option 1 or 1A
Quintana - Movistar hasn't been good this year so that hurts - Best climber in the world right now but he is not good at TT. This year's TDF does not have a lot of ITT miles so this could be his year.
Contador - Great team - Contador is the best grand tour rider of his generation but he ran out of gas towards the end of the Giro and going back to back is very hard
Nibali - Very good team - Nibali is the defending champion but has looked bad this year. However that isn't unusual for him. He could be on the podium or not in the top 20.
Van Garderen - BMC needs to get TeJay a super domestique. As is, he ends up having to fight solo for way too long. He's a step behind Froome in most ways that really matter for the GC
Pinot - Finished on the podium last year - I just don't see him doing it again. Though the lack of long ITTs favors him.
Bardet and Peraud - AG2R had an amazing 2014 TDF and these two were phenominal. I would expect one of these guys (I'm leaning towards Bardet) to finish in the top 10.
Talansky - I love the kid and his grit. With Ryder Hesjedal helping him, it is possible that he could make some noise. The problem is that Cannondale-Garmin always rides at the back of the peleton to conserve energy which means they get caught up in all of the wrecks. I would love to see them ride a bit further up in the group to avoid some of that stuff.
Sprinters - If you would have asked me two months ago, I would have said that I didn't think Sagan would do anything and that Kristoff was my favorite for the Green jersey. I also thought that Kittel would continue his dominance. However Kittel has been very ill and isn't going to race. Kristoff peaked for the classics and hasn't looked the same since. Sagan has really turned it up. I don't think he'll win many stages, but he looks to be back to being the guy that can win the Green. His biggest competitor for the Green jersey is Degenkolb. With Kittel not being at the tour, the whole team is lined up to support him. He is a lot like Sagan in that he isn't a classic sprinter. He can climb and he can ride the cobbles. I am betting that Degenkolb with the Giant team gives him a great shot at usurping Sagan who will be on his own as the rest of the TS team is there for Contador.
TTT - The best time trial team is Orica GreenEdge. They have edged out everybody pretty much all year at that discipline. Sky and Ettix are right there with them, but somehow they always seem to come through by a thin margin.
This year looks to be one of the hardest tours in memory. With multiple cobble stages and a ton of mountain stages it looks like it is going to be an amazing tour. If you like sprinters, this isn't your year. Personally, I find sprinting stages to be mostly boring with about 2 minutes of action. Mountain stages are always fantastic.