being the 19 hunter class hero, i felt obligated to reply here to help you out.
for some reason, lots of 19 hunters have jumped on the careful aim bandwagon. since i don't know any other way to put it, i'm just going to say it straight up: careful aim sucks at 19. don't get me wrong, it's a great talent for the hunter class, and at higher levels it's a must-have. you're going to see people flame me for this reply, so you'll just have to trust me on it. if it makes you feel any better, you can ask around to see what kind of a player i am on my 19 hunter
at level 19, you only have 10 talent points. your first 3 always go into hawk eye unless you want to pvp gimped. that leaves you with 7 points. your 1st priority is to get hit capped, so if you don't have 5%+ hit on your gear, you're going to want to fill points in focused aim until you do. after that, the choice is up to you whether you want to get imp concussive shot or go straight crit (i go imp concussive since i only do arenas).
crit is the most important stat for any physical dps twink class. crit wins games. 30-40 extra attack power does not win games. the magic number you want to shoot for is 20% crit without gimping your other stats too much. hunters get a LOT of crit per agility at 19, so you will be able to get relatively close to 20%. i'll be right around there after i pick up skinning on tipdrill (my hunter).
in addition to providing a lot of crit, agility provides a LOT of dodge at level 19 for hunters. tipdrill has over 33% dodge with monkey on. that's a lot of dodge, especially after the dodge rating nerf for 19s. that's 1/3 of hamstrings, wing clips, gouges dodged - not to mention all the straight up melee dmg
.
i see all these 19 hunters with sub-1000 hp, 10% crit, and 270 attack power, and i just think....why? not to mention they don't have hawk eye maxed. anyways, i'll get flamed by a bunch of careful aim lovers, but i can tell you this with 100% certainty coming from the 19 hunter class hero: agility is king for 19 hunters.
edit: make sure you get a 22 intellect weapon as well - you'll use this in arenas in order to give yourself 330 free mana. you'll switch to your 25 agi wep after you use the mana.