well it depends on what kind of riding you want to do. i had a very stiff boot as my first pair, because i had no idea boots had different flexibilities. now that my riding style has developed, i bought boots according to my needs. i like riding park a lot, and hitting small-medium/large jumps. im not interested in bombing down runs as much as doing flatland tricks and park, so i bought slightly more flexible boots. my boots are flex 5 (on a scale of 1-10 i think, with 1 being the most flexible).
what kind of riding suits you?