Well, to try and help out, here's my go at it.
Holy=Heal
Ret=DPS
Prot=Tank
For PvE grinding Prot is a fun way to go for AoE grinding. A build you might go for for AoE grinding is:
http://www.worldofwarcraft.com/info/classes/paladin/talents.html?055000200000000000000530513300002152515010520000000000000000000
or
http://www.worldofwarcraft.com/info/classes/paladin/talents.html?000000000000000000000530513300002152515010520500122200000000000
For PvE 5mans or raiding as a tank you might want something like this:
http://www.worldofwarcraft.com/info/classes/paladin/talents.html?000000000000000000000530513300002152515010523500002200000000000
As for PvP, I LOOOOOVE this build:
http://www.worldofwarcraft.com/info/classes/paladin/talents.html?000000000000000000000530513300002152515010520500122200000000000
It's the same as the one I'd use for AoE grinding just FYI. But it's fun as hell in PvP. I use it for surviving Flag runs in WSG, holding points in AV, and manning a flag in AB long enough for reinforcements to show up. Quite an annoying build for others.
As for weapons, I suggest 1hander and shield for Prot and Holy and a 2hander for Ret. But for Holy, honestly just go for better stats.
Hope my opinion helped.
::EDIT::
Forgot to include a Ret build heh. I haven't used this yet, but it's what I would try out first if I do go Ret sometime:
http://www.worldofwarcraft.com/info/classes/paladin/talents.html?055000000000000000000000000000000000000000523505122203105331251
Edited, Apr 24th 2007 5:22pm by TacticalRage