The stained clay is what I want more than anything. Its the first block in vanilla or mods that actually allows for modern builds without using a texture pack. I'm very excited about them. Finding a canyonland BoP biome makes clay collection a breeze.
There are plenty of colored blocks in modded minecraft.
I use Misa's so only vanilla blocks are changed for me.
I don't find any of the blocks ugly.
It's really a personal opinion as to what you like and don't like.
I will never play vanilla again so I will always have options from mods.