Lord: Hector. Ike is a close second, but close only counts in grenades and horseshoes.
Myrmidon: Edward. He's cool! And my friend noted that he's a bit like Genesis from Final Fantasy when he's promoted.
Soldier: Oh, Nephenee, how I adore you~
Fighter: Well... Nolan. I would say Ross, but he's a Pirate. ...*cue Pirates of the Caribbean theme* >_>
Mercenary: Gerik. Gerik is a butt-kicker. ...Actually, I don't know why, but I think Caellach's cool too, mainly for his personality and the bit of background he has. Not as a unit, though.
Knight: Honestly... uh... I'm gonna say Black Knight/Zelgius. As a normal person, probably Gatrie.
Pirate/Brigand/Berserker: Ross, man. Ross.
Cavalier: I like Titania. C: Not so much in Path of Radiance, but still.
Pegasus Knight: ...Umm... Hmm. Fiora. She looks like Nephenee? XP; I don't care for Pegasus Knights.
Dracoknight: Cormag... his whole "rawr I avenge my brother" thing is awesome. Haar's the Black Knight on a dragon, though. >w<
Archer: Shinon's cool. What's the problem?
Thief: ...Volke XD Thieves are kinda ehh other than thieving.
Cleric/Troubadour: L'Arachel is amazing. Enough said. Since she can generally cap her speed and luck, she'll steamroll through Lagdou until Floor 10 even without a bunch of stat boosters.
Mage: Well, I'm partial to Soren, I guess. As a unit, he's great.
Shaman: This is hard. It's between Pelleas and Lyon. Technically Lyon's his own class, so... Pelleas. I like his story, and him as a unit...
Laguz: