It depends if you want to go for all out tanking or not. If you are going for all out tanking then I would suggest this sort of build...
http://www.wow-europe.com/en/info/basics/t...000000000000000Its basically a core prot build using talents from holy and retri to make you mana efficient as possible. I've also tried to squeeze out some talents that will allow you to judge more often and squeeze out as much aggro generating damage as possible.
Though of course if you are wanting to heal every now and then, then I would suggest your build as it has a bit of utility built into it. Though this will be more for chucking out a few heals on yourself. To be a viable healer, you would need at least the first 20 points in the holy talent tree and make up the rest through healing gear.
And in answer to your little question. Yes you do need blessing of sanctury. I found that it is essential to have that, reckoning, imp. holy shield and avengers shield. These 4 spells will make up your main combat meat and potatoes. Ardent defender is also useful to give a healer a bit of slack when the pressure is on.
To be honest, I've found it very difficult to create a fully satisfying pally build. Every combination always leaves you squirming over something you think you really need but cant have. It comes down to your playing style really and what you feel will be essential to what you want your pally's role to be.
Hope this helps
