I tend to change classes a lot and i want to stick with one of these two, whick one should i use.

Soufian is definitely wrong. I've been playing pally for 5-ish years, and I can tell you that ret is at a low point right now.

-Warrior dps > Paladin dps (at max level)
-Paladin tanking is easier than warrior tanking, but most people I know say that warrior tanking is more 'fun'
-Paladins can heal, warriors can not

I may be biased since I've played pally for so long, but I don't see why you would choose warrior unless you were going to be PURE dps. Pally tanking is literally 6 buttons and it's easier to keep aggro, not to mention you can heal yourself pretty easily if your healer is stupid. And I know you said just for dungeons, but if you're going to be questing, you're not going to be able to heal yourself at all if you're a warrior.

Warrior is harder to master than a paladin - Paladin versitile - Druid Tanking is lame

as long as your tank you will lvl the same speed

a warrior is mostly a tank
a paladin is mostly a dps

if ur a tank you will get faster to a dungeon
then a dps

[best thing to do is become a druid because it has dps/tank/healer]