I absolutely adore the changes made to the Ranger. I've wanted to play a Ranger for a while, but the class always really looked unappealing to me beyond 1st-level. Now I can see myself playing one all the way to 20th level. I think it's fantastic.
The Barbarian I really liked when it first came out in 3E (Well, not really. I liked the Barbarian ever since The Barbarian's Handbook for 2E came out. Think I still got that book lying around), and they only made him better.
The Paladin, my favorite class, has seen some marked improvements. I don't much care for losing Lay on Hands at 1st-level, but the rest of the changes, the reshuffling of levels for powers, I can understand (With the exception of Turn Undead. I don't like it at 4th-level). I'm elated at the addition of "Knowledge: Nobility & Royalty" and "Sense Motive" to the skill list. I also like the additional Smite Evils as one progresses in level (Would've preferred a Bonus Divine Feat at every 5 levels, with Extra Smiting being one of a couple choices, but oh well). Would've preferred Cure Disease be made part of the spell list, though, rather than remaining as a class ability. Though speaking of that spell list, I love a lot of the additions. Especially that 2nd-level list, which was really lacking in 3E, and left the Paladin without anything interesting until 3rd-level spells became available. As for the Paladin's Mount, I like that change a lot, too.
I also like the changes to the Monk. Especially the versatility of being able to take one Feat or another, rather then being shoe-horned into taking a specific ability. I also like that the quarterstaff was made a Monk weapon. In 3E, the quarterstaff was supposed to be the primary Monk weapon, but there was really no reason for someone to take that when nunchaku's were readily available. I also like the changes to the Monks attacks, his extra attacks coming from Flurry of Blows, rather than having a separate BAB chart for his Unarmed Attacks. They cleaned up the Monk very nicely.
All in all, I like all the classes, now. If their goal was to give people a reason to progress through one class all 20 levels, then they succeeded, because I'm more hesitant than ever to multiclass no matter what kind of character I play.
