My style is a bit of both. I roll the standard 4d6, drop the lowest die and arrange to taste first. I look at the numbers and try to envision my character concept. Its easier if you are using a point buy system, though. Once that is done I go and picked the best class that represents the character.
In the current campaign I am playing I have a character that has the ability to close people's wounds with a mere touch, by expending a bit of spell and personal energy (takes subduel dmagae each time he does this). Also he is a mastercrafter of weapons and a scientist (as much as one can be in a medieval setting). He is often at odds with himself as he can heal and bring life while at the same time he is a warrior that uses his inventions and weapons to take lives. So his personality is that of a walking contradiction.
Game mechanics wise he is a Mage Blade (modified from Monte Cook's AE) with various key feats that allow him to heal. Placed his skill points in Craft Weaponsmithing, Heal, and Knowledge Science has being his primary skills.