I think that having experience in more than one martial art can be very beneficial. From what I understand, many of todays senior aikidoka who were uchi deshi for O Sensei had previous experience in other martial arts. In fact, I recall reading somewhere that prior experience in another martial art used to be required prior to beginning aikido training under O Sensei. I came to aikido after training in other martial arts for more than fifteen years, and for me the greatest benefit was that my prior experience helped me realize that aikido is the best fit for me among martial arts. Although I would probably still be practicing taiji along with aikido, if I could find an instructor near me and I didn't have my existing family and work responsibilities (probably the biggest barrier - time). Orenb, I don't know how long you've been studying aikido, but one thing I would recommend is that the practitioner developes a strong understanding at least in the basics of one martial art before trying to simultaneously begin and practice another art. This is because there is the risk of "blending" the basics and subleties of each art, thus missing out on the full benefits of each art. I don't mean to say that those individuals who have and continue to practice only aikido are better or worse. On the contrary, some of the sensei and sempai I respect and admire most have focused exclusively on aikido. I only think that some people might enjoy and benefit from being exposed to more than one martial art - it all depends on the individual. IMHO.
[Edited by BC on July 20, 2000 at 08:57am]