Lemme drive your car.

Hmm...you've seen most of the same ones I have. Happy Lesson was fun while it lasted, but the ending sucksmonkey nuts. I would maybe recommend the following...

Mahou Sensei Negima
First off, the manga is 1000000000% better than the anime. Negima is by Ken Akamatsu, the wonderful ecchi brain behind Love Hina. Basically take a 10yr old boy wizard in training and make him a teacher at an all girls highschool in Japan. Combine ecchiness and fun magic crap and you get a decent series. The anime is "okay" at best but the OVA is good and the manga is one of my favorites. The regular season is available for purchase on DVD, the OVA is available for torrenting.

Sister Princess
Take a high school guy, put him on an island, and give him 12 sisters. Each has her own personality, interests, and whatnot. The series is a decent, cute watch, but there really isn't much story or development at all. If you want something to pass the time, then Sister Princess is okay. However, if you're looking for plot or fanservice, this one will put you to sleep. Available for purchase on DVD.

DearS
Take Chobits and replace the androids with aliens. That's about it. A little more on the ecchi side of things (especially in the manga) but it's a fun watch. Being a short series, it's easy to get through in a hurry as well. Considering your kill-list there, you'll probably enjoy this series. Not as much of a harem style anime, but there are 3 girls (4 if you count his sister) that are after the guy. Available for purchase on DVD.

Shuffle!
Gods and Devils are now part of our own world. Tsuchimi Rin has been chosen to marry either the god princess or devil princess and become either the ruler of the Gods or the ruler of devils. Couple this with a childhood friend that he lives with, a loli-devil girl whom clings to him, and a best friend who may turn out to be more than that, and you get harem gold. Similar to Love Hina, but far better in anime form. Also, the drama in this series kicks @ss in the second half of the series. I recommend this series for you. Avoid Shuffle! ~Memories~ though. It's basically just a big@ss recap aside from the last episode which is fanservice goodness. Available for download via torrent.

Lemme drive your car.