SMP's Revival is my all-time favorite 16x16 pack. My computer isn't that great so I can't help you out with anything a higher resolution than that. However, a lot of people mistake SMP's as a 32x32. I'm a hipster when it comes to this pack, I used it before the Yogscast did :laugh.gif:
Here you go, one of my personal favorites. (http://www.minecraftforum.net/topic/72747-faithful-32x32-pack-update11-support-mods-11/). Its basically the default pack at 32*32. Looks nice and lets you keep the default look if you like that.
~Rev
Leostereos RPG (also amazing 16x)
Woodpack (16x Realistic)
Isabella ( 16x)
Johnsmith (32x, realistic)
Dokucraft (32x, RPG)
Some of the best ^^^^