If you are doing Aikido for a hobby, then maybe you don't need to be interested in learning Jiu-jitsu or Judo. But if your interested in practical self-defense, then why not study Judo and Jiu-jitsu? There is no law in our land that prevents you from training at more than one dojo. Most guys I know that teach Judo also have a dan rank in Aikido as well. The three, Judo, Jiu-jitsu, and Aikido go nicely together. Have fun!
I agree with almost all of this.
Monty, who did you learn your Aikido from, and how long did you train in Aikido for? Which style of Aikido do you teach your students? What styles does it derive from? Do you give them Aikido ranks, and do they go to Aikido seminars, or are they mainly encouraged to practice Aikido in their home dojo? Is Aikido taught as a side-bar, or are there actual formal Aikido classes?
Whom do you consider an Aikido expert, and who are the people who have taught you this Aikido that you know? I'd like to know so that if I ever run into them at a seminar, I can train with them. Do you ever go to Aikido seminars?
As for practical self-defense... for those of those truly interested in self-defense, I would recommend broadening the scope of your studies into other areas.
A true self defense expert would also be an expert in first aid (to stop the bleeding from all the knife fights that someone so interested in fighting would get into), know at least a little bit about the law (to keep out of jail from all the fighting, or keep from being sued in general), know about nutrition (got to keep that cholesterol down!), proficient in defensive driving (car accidents are a very common killer), be good with computers (watch out for that identity theft), be an expert marksmen, etc.
Personally, I am not interested in self-defense. I don't have time for studying so many things. Taking so many classes takes time away from my busy video-gaming schedule. I study Aikido for fun and as a hobby, and for what I perceive as being its positive effects in the other areas of my life. Oh, and maybe it helps with the cholesterol too.