I recommend anyone who hasn't watched way too much anime in their lives skip Gintama, it's full of inside humor (which I love, but you'll be confused most likely).
If you're going to watch Fullmetal Alchemist, skip the original and watch Brotherhood, as it's much better. Yu Yu Hakusho is very DBZ-ish. If you want to really see how far animation has come since the 90s (the actual visual animation) watch Basquash. It's fun and silly. Ruroni Kenshin is always a good one. I didn't like Gurren Lagann at all. Full Metal Panic is fun (gotta watch all 3 series of it). Samurai Champloo and Cowboy Bebop if you just want some dumb action. Eden of the East is pretty awesome as well. Just go here http://myanimelist.net/topanime.php and start looking around. You'll find plenty to watch to last you multiple lifetimes.
