Arts which complement Aikido

I've seen that many people seek to complement their Aikido training by studying other martial arts, such as Karate or Brazilian Jiujitsu. I am interested to know what others think about this, and what experience you may have? Thanks.

I may make things worse but here goes............What is 'compliment' mean and what does it mean to you is more of a question. How to define compliment is a real dilema. Look at SHOTOKAN KARATE, it is excessively linear, and a "one punch one kill" philosophy. I see Shotokan as a 100% opposite than Aikido. Yet you will find more Shotokan Karate-ka that train in Aikido than any other style of Karate. So the compliment here may be that both styles are Japanese.Therefore from the same culture may make it a good compliment where Kung Fu a Chinese style may not. However, the Chinese movements are more suited to Aikido. I worked the a Tiger and Snake Kung Fu student one night and we showed each other our variations on almost the same techniques. We were sharing Japanese and Chinese arts yet they complimented each one nicely. I know of an Okinawan Karrate Sensei who studied 'old school' Shito Ryu, added Aikido and Jujutsu and Judo to his art and it was a very well rounded art. So I think it depends on where you are weak, and what needs complimenting. Judo I think is comparable, but I don't see it complimenting as much as say a striking art. So it really depends on you and what part of your art you want to compliment. If you want ground work try Brazillian Jujutsu. Striking, find a style that appeals to you. One thing I found was that Arnis was a great asset to what I do, as you drop the bastone and you use your hands like a weapon. Similar philosophy with Aikido and the sword, so Modern Arnis is what I see as a great compliment, but that is for you to decide

My former aikido sensei teaches arnis, and would agree with senseilou, as would I. It has been my experience though that almost any style compliments aikido, I would tend to go with something that is more of an entry level style (no offense to anyone) like a tkd, or karate, or go the route of the people that I train with and do shorin ryu. We all did aikido first and then switched, strangely enough some of us ten years ago and some of us at any point since. This style compliments aikido but the aikido should be done first, because the breakfalls help a great deal, and the majority of the throws that we do are the standard ones from aikido(or judo, jujitsu, etc) The more I type here the more I find this to be a difficult question, in some ways aikido is best approached with an "empty cup" and no prior knowledge, I know that my other habits made aikido awkward. I recommend tai chi in accompaniment with any style, but you should learn to strike and parry along with your aikido, so even boxing would be helpful. Aikido is what many of us call a middle style, striking first (tkd, boxing, shotokan, kickboxing,etc.), then holds and locks and throws (judo, jujitsu, aikido, etc.), and finally pressure points (kung fu, shorin ryu, etc.) Very few styles have all of these so you need to figure out which way you want to travel the steps, as far as the middle step goes, aikido is one of the best ways to get through.
I hope this wasn't to confusing, it was supposed to be simple. And I hope that I don't offend anyone with this post, as this was not my intent.