i haven't watched any of these (except sao and the pokemon anime, which weren't really my thing) but i'll just go with One Piece because I like the art style and variety in character design. I personally prefer casual trash like osomatsu and nichijou.
soul eater looks really cool though it's not on the list
shrek ftw
I only watched 2 of the shows here listed on the poll.
The Pokemon anime is decent, but it can be a bit cheesy from time to time and the main character doesn't develop at all until the recent seasons. Definitely check out the X and Y series though, I've heard it's been really good as of late.
One Piece has some really interesting plots and unique goofy character designs, buuutt you'll be at that series forever since it's a long runner and it's still going on for over 17 years at this point. And unlike the Pokemon anime in which each series does have a unique plot so you can jump in at any season if you're new to it, One Piece is overarching and you'll have to start at the beginning if you want to know all of the plot details and characters. Admitely the pokemon anime has that as well, but since Ash doesn't really change in between series it's not as big of an issue as One Piece is.
I've heard good things from Fullmetal Alchemist Brotherhood, so I would check that out as well. Though the 2003 anime isn't that bad either, though it's drastically different from it's source material.
But since we're on the subject of anime to suggest, definitely check out Jojo's Bizarre Adventure, Digimon Adventure and Digimon Tamers, Ranma 1/2, and others that I'm too lazy to list down.
Brotherhood for sure. The overall story is just the most appealing and feels very solid IMO. Most of the others come across as clique and/or drag on way too long.