A few things to note on Holy Paladins builds for 25-man raiding:
1. You'll most likely have 2 Holy Paladins, so only 1 needs to get Improved BoW. That leaves the 2nd paladin with 2 free talent points that have be spent before moving past Tier 5 and then past Tier 7.
2. If raiding with an Unholy Death-Knight, they'll have
Unholy Aura, saving you 2 points in from the ret tree in your standard 51/0/20 build.
3. Improved Devotion Aura doesn't stack with Tree of Life, so assuming you have a resto druid in the raid, improved devo doesn't grant any bonus other than a little more armor. Anyway, it's a very easy and natural talent for prot paladins to pick up if you bring one along. It's definately not worth picking up if you are going the holy route... way too much wasted talent in the prot tree to get it when you could just bring a resto druid.
So, assuming those two points, it'd be naturaly for the 2nd paladin to go for a 53/0/18 build and pick up aura master with improved concentration aura. I think this build for the 2nd paladin would work well for the group:
Holy 53/0/18
The first paladin (assuming you have an unholy DK, which we'll be bringing) would use a 51/0/18 build with 2 points left over to put wherever suites them best for the content.
Unyielding Faith,
Purifying Power, or
Improved Judgements would all be decent places to put them.