Originally Posted by syhr
Conditioning is relative; practice enough BJJ and you will get good BJJ conditioning, practice enough KF and you will get good KF conditioning.
Not sure about your current fitness, but if you're an an exercise nubee then look to your basic fitness first, regardless of what you wanna train in; get in the habit of doing basic regular exercise (home workout, gym, etc). This will build your basic strength and endurance, which apply to any art you want to practice.
After than, visit each of the dojos in the arts that you're interested in. Watch a few classes, talk to the staff and students, try to get a feel for whether it "feels right" for you. This has been discussed endlessly on the internet; a good primer is the MA FAQ (http://www.faqs.org/faqs/martial-arts/faq/part1/
) Section 5 "How do I choose a school".
Once you've done all that and chosen a school, any good instructor should be able to provide the best "bang for buck" conditioning exercises which are most relevant to that art.
I agree for the most part. I disagree about delaying to build endurance before starting. Get in and start working. Endurance will come.