Is Book of Exalted Deeds allowed in your game? If so, I'd go with Fist of Raziel combined with 1 level of Prestige Paladin, if you like it - the only trick is you can't take the 4th level of Ordained Champion if you want 9th level spells (which I'll assume you do). I'd stay away from Hospitaler, but that's just my opinion - I think there are other, better ways to spend you levels.
If you can take Fist of Raziel, I'd go: Cleric 4 / Ordained Champion 5/ Fist of Raziel 10 / Prestige Paladin 1. Gives you 6 smites per day, I think.
If you want to finagle divine grace in, maybe go:
Cleric 4 / Ordained Champion 5 / Prestige Paladin 2 (or 3, since it doesn't lose a caster level) / Anything that doesn't lose caster levels. Contemplative is nice, so is Sacred Exorcist, etc.
The Cleric handbook is a great reference:
http://brilliantgameologists.com/boards/index.php?topic=420.0