Hexblade is interesting. I've seen it used in a lot of builds -- as a full-BAB entry into Dragon Disciple, for example. Never had one in one of my games, so I don't know how well it plays. On paper, it looks a bit weak.
Swashbuckler is bad. It's basically a three-level class. If you're okay with players taking three levels to get that one special ability, fine. But consider porting the Unfettered from Arcana Evolved instead.
Samurai from CW is terrible. It's weaker than a Fighter. Very sad.
Knight from PHB-II is okay for a PC, but as a DM I don't like it. How would the players react if they met a Knight NPC? "No, sorry, you don't get to pick who you attack. You have to attack this guy here. It's his special ability."
PHB-II has some great ideas and classes, and some really great Feats. This book makes it actually worth playing a Fighter. The spellcasters are good, too -- Duskblade is cool, Beguiler does his job like no-one else, and Dragon Shaman is a Marshal with good mechanics and decent flavor. The spells in the PHB-II seem better thought out than a lot of the spells in the Complete books.
For new fighter-ish classes, my favorites would be the Crusader, Warblade and Swordsage from Tome of Battle. They compare in strength to spellcasters.
- - - - -
If I were making a new game, these are the classes I'd make sure had a place (in addition to the usual Core classes):
- Binder
- Crusader
- Dragon Shaman
- Dragonfire Adept
- Favored Soul
- Scout
- Spellthief (weak but cool)
- Swordsage
- Truenamer (weak but cool)
- Warblade
- Warlock
Cheers, -- N