Angel Beats too.

I guess

Angel Beats!!!!

I haven't seen Soul Eater (and don't really plan on it), but I choose Chobits over Angel Beats because the ending doesn't leave loose ends. Both anime's are good and keep you guessing, and to be honest, Angel Beats is better at that. However, it has a very... ahem... ambiguous ending, and that pissed me off. Chobits, on the other hand, had a good and solid ending, all questions answered.