I dunno you, but when you hear the word "smite" you expect a sudden and extremely painful rebuke. Generally you associate the word "smite" with the words "god" and "lightning".
Pathfinder's Smite is more of a Mark than anything else. Compare the Smite ability of PF to the marking ability of 4E Paladin, and you'll notice some similarities. While it's effective (I can't deny it doesn't), it doesn't really feel like a smite, but more of a mark. Case in point: Mark of Doom, where each time the enemy attacks you, it receives damage. Or Mark of Judgment, where each time you hit the enemy, it takes extra damage. It's not a sudden and extremely painful rebuke, and much less "strike down with godly force". Perhaps "injure with divine power", but the original smite did mostly that. What's worse, it feels like something you could replace Favored Enemy with, and it would work very nicely.
I do approve of something from 4E, and that's the rider effect they gave to smites. So not only you deal extra damage, you also deal stuff like stunning, blinding or nauseating; the effect is so strong it essentially halts the enemy in its tracks. That isn't entirely worth daily uses, but it does make for a much stronger, much better smite.
So, while PF Smite Evil does have the mechanics to make smite attacks usable per day, it doesn't feel like a smite. But, the smite evil ability from D&D isn't really worth restricting to daily uses. If the OP wishes to go the PF path, I can't say anything, but if he insists on using the 3.5 edition of Smite Evil, at least he should consider making it a per-encounter use, since that way you'll ensure the Paladin's damage potential will remain worthwhile.
I don't like much what PF did to the Paladin, though I must admit it's much better than 3.5. On the other hand, while a bit more "conservative" on terms of advancements, I like what Turbine did with the Paladin, though it could improve a bit more (adding Intimidate as a class skill, rechargeable smites, extra uses of Lay on Hands; still, they lack a proper damage ability other than smite, and sword & board is apparently a bad idea for any martial character, so you either go 2H or go against type and build a TWF Paladin).