If you've watched Steins;Gate, something along those lines.
I did, but Steins; Gate is a masterpiece, finding similar anime is a toughie. Well, just for your pleasure, I can throw some harem, action, funny, romance, mecha, something-something anime just for your sake. Lets see...from the top of my memory...
11eyes, packed with action, a hard to follow storyline, and some romance here and there. I enjoyed it, though it felt a bit incomplete.
Heaven's lost property is a good romantic comedy if you're into that sort of thing, it will definitely make you laugh.
sword art online is a recent breakthrough, it has amazing characters, story, etc...
Full moon is a bit of a drama and story involved one, I enjoyed every minute of it ^_^
some random titles now...shugo chara, inuyasha, the girl who lept trough time, shuffle, high school of the dead, seiko no qwaser, soul eater, after, higurashi when they cry, elfen lied, seitokai no ichizon, bakugan...honestly I don't think any of these fall in the category you asked for, but w/e.
I LOVE ALL ANIME. DEAL WITH IT.
Also, hopefully I didn't butcher any of the names I mentioned.
Also, if you're really into anime and want some good anime, I know I have a text document where I put like a list of 500+ anime on my floppy disk somewhere...ok, I'm just babbling at this point. I'll stop now ;_;