IMHO, arts like Judo, Brazilian Ju-Jitsu, boxing, Muay-Tai, and similar arts that require a student to compete against a fully resisting opponent are far more effective in a fight than those using only katas and/or "tag" type sparring. The arts I listed give you immediate feedback if you have poor technique. They also help weed out the techniques that don't work.
Obviously, the best fighters will be trained to fight fully resisting opponents from striking as well as grappling. While Judo only focus' on the grappling and throwing side, the opponents are resisting those and trying to do the same to you. I think it's a good idea to start learning grappling and striking arts separately, and once you've become somewhat profficient, incorporate them into your own "game".