In my experience, nothing beats a scruffy random-bred alley cat that picks you on its own. The pure breed that I think has the best personality is the Manx, and I've owned two excellent ones before. The two pure breeds I find most attractive are short-haired Scottish Folds, Ragdolls, and Turkish Vans, but I wouldn't list any of those as my favorite because I've never had the experience of owning any of them.