Watch PSME (Please Save My Earth). It's one of the oldest animes I've watched (saw it when I was a wee tyke
), but it's also one of the best I've seen. Very unique plot. Watch the English dubbed version on YouTube or something, and you may need some help understanding the plot. (If so, look around, or you can ask me.) The Japanese version, surprisingly, wasn't as satisfying as the dubbed one.