It depends on what you want from the cat. I mean, do you want a lap pillow or an athlete? Long-haired or short-haired? Are you looking only for a purebred or would a moggy fit the bill? Do you want to pick the cat off the chair or off the walls?
Lap pillows include Persians and other similar breeds. Athletes would include the Siamese or Oriental Shorthair (both very intelligent) and other Asian breeds. From my experience, cats with more "round" body shapes are more likely to be the lap babies, while those with more muscular or lean bodies tend to be more active.
I have 3 cats, all with different activity levels and personalities. I have a Himalayan who is very mellow-- so was her sister. My Birman mix is more active, but my Siamese is a ball of energy! He really does climb walls (and has me doing the same some days). I swear he's part cat, part d*g and part monkey. They're all different, as are all cats, and do*gs and kids--- and each one is "the best cat breed" for different reasons.
Perhaps the question you need to ask yourself is, "What is the best breed of cat for ME?". If you don't want a high-maintenance cat, for instance, then perhaps a short-haired cat is best for you. If you want a mellow kitty, consider one of the "round" cats like a Persian or British Shorthair.
The various cat-fancy organizations have breed standards available on their websites if you're determined to have a purebred. That's a great way to learn about the physical and personality traits of the different breeds. But remember that a "plain ol' moggy" (mixed breed) might be the one who wins your heart. You can find tons of them at your local animal shelter or rescue group. You'll be doing some poor kiddo a huge favor and in return, you'll have a good and grateful friend for years to come.
Check out the links I've provided for some info on different cat breeds. They're a great place to learn about the different breeds and their requirements. Hope that helps.