Level 10-34: Retribution.
Talents:
http://www.wowhead.com/?talent=qZZVbxtbzu
Many will ask why Pursiut of Justice, and this is why: You run ALOT on lowlvl, those 8% do help really much tbh, not to mention while getting to new zones (Traveling from Silvermoon to Barrens takes a while tbh), and dont forgett getting to Hillsbrad without summoning escort.
Judge with Seal of the Crusader after lvl 20, before you will do more damage by just judging with Seal of Rigtheousness.
But at 20, you will be able to get Seal of command but without the luxory by getting the weapon alliance get with its 99 maxdamage (totaly imba at lowlevel) and kinda slow speed. We will be using Sin'Dorei Warblade
http://www.thottbot.com/beta?i=5644 rather than wasting time to get our lvl 20 polearm (wich costs 1g or 80s if honored to learn)
http://www.thottbot.com/beta?i=5335 . By the time you will have this polearm, you would easily gain 1 or 2 levels by questing - waste of time IMO.
The thing is now - we wont have a slow 2hander like alliance paladins, wich makes seal of command weak - due to the PPM system is best with slow 2handers. I found Seal of Righteous doing more damage from 20-40, when I had Judgement of crusader up. Due to SoR cannot be dodged / missed / parried it will give more DPS than SoC. This changes later tho, when the new ranks of SoR doesnt get alot stronger like it do on lowlevel and when your gear gets better and better (Seal of Command scaling is extreeme - bonus from Attackpower&Meleecrit&Spellpower)
On the beta (and my lowlevel pally Ive played with a while ago) used SoR from lvl 1 to 40 due to I didnt have any good 2hander (high dps&slow), and it went fast as well.
Aura to use: Retribution aura
Seal to use: Seal of Righteousness or Seal of Command IF you have a slow 2hander.
Option 1
Level34, respec to:
http://www.wowhead.com/?talent=aZVMth0s0x Protection.
Reckoning, is the ultimate grindtool we have. With it, we dont have to focus to get intellect (to being able to judge for DPS / heal up often etc) since it gives us a 10% chance to double our melee damage for 8seconds, at the cost of getting hit (wich you get when you grind). Protection gives alot of nice defensive abilties as well, such as Thoughness -10% more armor / Improved Righteous Fury - 6% damage reduce.
Aura to use: Retribution aura
Seal to use: Seal of Righteousness
Option 2
Stay with Retribution up to 45, then respec to reckoning+SoC. Only do this if you have a slow 2hander with high maxdamage, else SoR will be more powerfull if you have a fast 2hander (wich is good for SoR)
http://www.wowhead.com/?talent=qZZVbxtbcuVho
From level 35/45 to 59- go Retribution+Protection Continue with Retribution:
http://www.wowhead.com/?talent=aZVGth0h0xZVbxt
Reckoning + Seal of Command (at level 40, were you can get slower 2handers than before) will give exellent grindspeed. Using Seal of Command rank1 for grinding costs almost no mana, makes you never go out of mana, and being able to use more attackpower&crit gear

Aura to use: Retribution aura until you get Sanctity aura
Seal to use: Seal of Righteousness untill you get Seal of Command
59 and beyond! Time for Outland, this time you have to chose yourself, either if you liked this grind build or if you want to specify some other spec to do all the new instances (tank/heal or dps/support?)
I hope this helps many new paladin players, or even old ones as well who didnt level up for a while.
I have leveled 3 lvl 60 paladins myself, and Im planning to make a Horde paladin as well and this is the way I will go.
Edit: Updated a longer intro, wich more basic info about gear / talents.
Weapon guide:
20:
http://www.thottbot.com/beta?i=5644 (elite q in Ghostlands)
30:
http://www.thottbot.com/beta?i=8271 (from RFK)
40:
http://www.thottbot.com/beta?i=13234 (from SM, no bonebiter for horde but
http://www.thottbot.com/beta?i=7924 for a 1hander. Mograines might works better with SoR than SoC due to the fast speed. Good choise if you respecced to Reckoning already.
44/b]:
http://www.thottbot.org/?i=5704 (from Uldaman) thx Kaaleppi
50: http://www.thottbot.com/beta?i=12601 (from Mauradon) and http://www.thottbot.com/beta?i=3191 as 1hander
51: http://www.thottbot.org/?i=40261 (AV reward)
55: http://www.thottbot.com/beta?i=11000 from Brd or http://www.thottbot.com/beta?i=2366 from LBRS