I love Wizard, Bard, and Paladin.
The 5e Wizard is my favorite version of my favorite class.
The 5e Bard is awesome, now equal to my favorite Wizard. I am so glad the Bard went full-caster, and reconnected more to mythologically accurate Celtic Bard (Filí). Now the Bard is an extremely versatile class, able to represent so many different kinds of concepts. A reasonably accurate Merlin or Taliesin. Norse seiðr. Norse galdr. Norse spá. Likewise, a mythologically accurate shaman from many other cultures. An elven enchanter. A charming minstrel. A spellsinger. A courtly magician advisor. And so on. Especially as a DM, I find the Bard highly useful to portray variegated concepts.
The 5e Paladin. In previous editions, I never have any interest in the Paladin class. But for 5e, the concept, flavor and potency is growing on me.
I hope the Psion when it comes out − along with the psionic archetypes for Player Handbook classes − will count among my best classes.