Well.... for selfdefence purpose ? I guess you should drop all the high-kicking MA's, and of cause most of the weapon-classes. I have never tried jiu-jiutsu, but I guess you can find a very self-defence focused form of jiu-jiutsu, so maybe that would be a good art to pick up.
Bruce Lee's Jeet Kune Do is supposed to be very focused on working in real life so maybe that would be good as well.
Perhaps you can find a Karate-style or Kung Fu style that has self defence as a primary goal, but I guess that it's all and all more about which dojo you choose rather than what martial art or style you pick. Go see what they do in different dojos in beginners class and talk to the students and the teacher. That will give you a good impression of what they focus on in that dojo.
If you on the other hand want to practice a MA that complements you Aikido then perhaps Iaido or Jo-do would be good for you - not all that 'real-life-applicable' thoug.
Hope you find something that suits you.