I prefer creative and artistic levels, as well as the simple, symetrical, and organized levels. Here are some of my favorites:
I liked the spinning circles for some reason:
![Image](http://img222.imageshack.us/img222/4036/userlevelcirclemysteryqdi5.png)
I liked the swinging tail in this one:
![Image](http://img232.imageshack.us/img232/5684/userlevelkilltailju5.png)
Artistic...kinda cartoony actually :)
![Image](http://img222.imageshack.us/img222/71/userleveloctospider1487qb2.png)
Very symetrical:
![Image](http://img222.imageshack.us/img222/4443/userlevelorize1174vu6.png)
Simplicity:
![Image](http://img222.imageshack.us/img222/2052/userlevelshurikannr5.png)
Wow, i hadn't seen this one until you mentioned it, very cool:
![Image](http://img410.imageshack.us/img410/7757/userlevelriversidecity1se4.png)
I'm amazed what people have come up with, I never even considered making a level non-robotic-boss-ish when I first started.
(ok, maybe I went a little over the top with all the screenshots...o well...)
Feel free to post your own favorites.
~MD