Recommended Dilletante Powers
Dragonfrost (Sorcerer) (PHB2): If you're looking for a ranged basic attack, this is the way to go. 10-square range, decent damage, and it can push the enemy a square if it hits.
Eldritch Strike (Warlock) (PHBH): Weapon-based, and it counts as a CHA-based melee basic attack. It also slides the enemy a square if it hits. It serves as a fine alternative to Virtuous Strike if you'd rather select two other Paladin at-wills. Or, if you do plan on multiclassing with an arcane class, you want to outfit a melee basic attack with fun stuff like the White Lotus feat line (D 374), Quickened Spellcasting (AP), Arcane Admixture (AP) and all the goods that feat opens up, etc. Take the Melee Training feat to tide you over in Heroic Tier, then retrain that feat for Versatile Master when you hit Lv. 11.
Eyebite (Warlock) (PHB): A popular pick, but not optimal in most cases. If you already provide plenty of disincentive for an enemy to attack an ally (e.g. Hospitaler paragon path), then this one's value increases a ton. But other than that, you're better off with Vicious Mockery.
Furious Smash (Warlord) (PHB): A Chaladin who multiclasses Bard and takes Combat Virtuoso to use CHA for the attack with this power can use this one to devastating effect. Straladins should take Righteous Brand, instead.
Guiding Strike (Bard) (PHB2): Weapon-based at-will debuff to a defense of your choice. Awesome.
Jinx Shot (Bard) (AP): A CHA-based ranged weapon at-will. Perfect pick if you want a ranged attack but don't want to worship Corellon or otherwise fiddle with multiclassing for implement usage. The effect that can send an enemy to the floor is great, too.
Righteous Brand (Cleric) (PHB): For Half-Elf Straladins who want to add some extra Leader to their arsenal and hand out enormous attack roll bonuses to melee allies like candy.
Sacred Flame (Cleric) (PHB): Ranged radiant attack against Reflex that can give an ally a solid amount of temp HPs or allow a save. Good choice for a CHA/WIS Paladin/Cleric.
Twin Strike (Ranger) (PHB): This is the most damaging at-will power in the game, as Rangers themselves know and boast. Half-Elf Chaladins who want to dual-wield multiclass Bard and take Combat Virtuoso to use CHA for the attack, which works out perfectly since this power doesn't add ability modifiers to the damage, anyway. Of course, this is also the key power for the rare dual-wielding Half-Elf Straladin.
Vicious Mockery (Bard) (PHB2): Like the Chaladin's own Enfeebling Strike, but with a 10-square range! Implement-based attack vs. Will that slaps a -2 attack roll debuff on the enemy if it hits. Use this against a marked enemy to make it hell for the knave to hit your allies (cumulative -4), which is your job, after all. For that matter they're not gonna have an easy time hitting you, either. It's a Psychic attack, too, which means it can be enhanced by feats like Psychic Lock. Beautiful.
War Song Strike (Bard) (PHB2): And another Bard power. Noticing a trend, here? This one's weapon-based, and if you went with CON as your secondary stat, this one hands out a lot of temp HPs to allies.