I second what Natesnation said, the way he described it is how i couldn't, but wanted to.
i already bought my ticket for this year and booked my hotel room.
oh if you do go, you will need to practice patience as walking around can feel like waiting in a giant building sized line... but yeah costumes galore, good and bad, lots of guests (Stan Lee, Capitaine Jean-Luc Picard... i mean Patrick Stewart, Sam Lafayette and Russell from True Blood, Shane and Darryl from The Walking Dead, the guys from boondock saints (evne though one is also part of Walking Dead, i know). great listing of guests this year. oh and a bajillion comics and independant artists, which i thought was really neat to see!
do get a good pair of sneakers too.
if you've been to the Ottawa Comicon this year, it's about 20 times cooler than that was...