Favorite anime would easily be FMA Brotherhood. Tons of reasons why I love it, but mostly because it has such a huge and diverse cast of characters that you really grow fond of. The 2003 version of FMA's plotline is pretty screwed up, but its still got Ed and Al (the main characters) who I absolutely adore for their humility, righteousness, quirkiness, fighting skillz, blah blah blah.
Technically not anime, but I also LOVE LOVE LOVE Avatar: the Last Airbender. I literally feel sorry for anyone who hasn't seen it, it's that good. Legend of Korra (the spin-off)'s ending is screwed up, but it still lives up to the Avatar tradition of excellence.