I don't want to say blue, but I really do like it. Although, a long time ago I've always been out to get a yellow partyhat! It's been something on my mind ever since I saw someone with one and a Cons Cape (t) and I loved it.. haha, the only partyhat I'll ever be going for is yellow.
So yellow.
Depends on the what you are wearing. If some random person with all the phats came up to me and said choose only 1 and u could have it, i would choose green just because i think it stands out the most, its the most bright, tied for 2nd would be blue and red, white next, yellow and purple i dont care much for, yet i would be more than happy with 1.