I think the Netherlands are going to provide the tournaments shock exit in the group stage, they've got some great attacking players but i'm not overly convinced by them, certainly their form since qualifying has been pretty bad (although i'd hesitate to take too much from games that had little meaning attatched to them) and although they got to the world cup final, it seems a lot of Dutch people aren't too keen on the manager and the style of play, although clearly they got to the world cup final so perhaps they're overly harsh on him.
Still, Germany thrashed them back in November, and although Portugal aren't the team they were 6-8 years ago, they're still a side who can give the very best a good game. Denmark are no mugs either and finished ahead of Portugal in qualifying, certainly capable of taking points of teams if not good enough to qualify.
Germany should get through top, Portugal second, Holland third, Denmark last. Whoever makes it out this group should have a decent game for the quarter finals as well, so you'd be looking at a semi finalists as minimum for the 2 who qualify.