Too biased towards India, eh?
Anyways, Australia, New Zealand and South Africa are clearly the top 3. The "c"-word tag should no longer be by South Africa's side now as we've seen how Miller and Duminy handled the situation after 83/4 vs Zimbabwe. England has a lot to achieve, and Morgan is most likely to get a Cookesque kick out of the side because of a string of poor performances, so he definitely has to perform in England's first match. Sri Lanka are always the "out of nowhere" team and without extraordinary performance(s), they easily manage the knockout stages (as we saw, they were in the final of CWC 2011 without extraordinary performances) so they are not to be taken lightly whatsoever. India are on to do something big, but sadly they do not have the side they need to get to (which is still possible), or win the final. Dhoni will surely need to do his best this time to successfully defend the trophy.
Meanwhile, on the other side, Pakistan never fails to deliver a surprising campaign in World-level series. Whether it is an epic comeback, or no comeback at all. West Indies are significantly vulnerable now due to no Bravo and Pollard, and overall a side that isn't that experienced or "good enough", simply, for the giants. Ireland have to be really cautious and show their best. The loss to Scotland was really demoralizing, but they have to improve and perform to raise their standards to what they were before (in the previous World Cup). Their main drawback can be considered the lack of form in their players. Scotland on the other hand, aforementioned, got a serious boost in moral due to defeating Ireland by a huge margin. Their narrow lost against the West Indies (by 3 runs) was also inspiring as they certainly are in the mood to cause upsets this year.
Zimbabwe is what we should not take lightly this year. Seriously, they have stunned me, at least, with their amazing warm-up performances vs New Zealand and Sri Lanka. Restricting the World's best team of the previous year to 157 runs without any more batsman left is quite amazing, and then again the second-highest score by a batsman was Ross Taylor's 11. Then they pummelled on the Lankans and defeated them in a totally one-sided 7 wicket victory, and the only reason they had to chase a higher target than what New Zealand managed was because they rested their better bowlers. Masakadza shone with a belligerent hundred.
Afghanistan's first World Cup won't be that good (as in, their performance won't be that good), but the fact that they made it to the World Cup alone is quite astonishing and amazing. Still, they might be able to cause upsets with a somewhat experienced squad. The same can be said for the UAE, except for the "experienced" part. Should still put up a contest against Afghanistan, though, at least. Bangladesh on the other hand aren't quite performing as of lately. Neither of their seniors, or performers really, have put on a show in the recent past. If Shakib al Hasan gives an all-round gem, they are able to win against even Pakistan, so they surely shouldn't be overlooked.
NOTE: The opinions expressed only represent my thoughts, not of any other. However, if you agree, I don't mind. Also, if there's a lot of appreciation or something in any of the teams' description, it's not intended and I am not biased towards any team specifically whatsoever. Patriotism or team routing on the other hand is a possibility, but just so you know about that anyways, I'm a Pakistani and tend to support my team in most matches in which it is participating. If Pakistan isn't playing, then Australia, New Zealand, South Africa and (a new addition to the list:) Zimbabwe are my favourites to win the match.
EDIT: You should probably make the title "ICC
Cricket World Cup 2015", and reserve a post in which you add all the match results (first & second innings team scores, 2 highest scores from both teams, two best figures from both teams and win margin), fixtures and anything else. Also,
ESPN Cricinfo has every match's analysis, ball-by-ball with commentary, scores, stats and pre-, mid- and post-match reports.