I like PureDBCraft (otherwise known as Sphax in certain forums.)
It is almost (so very almost) in complete support of FTB too (with the additional FTB addon to the texture pack.) I still don't know why they missed re-doing all the red rock textures when other Extrabiomes stuff was done. I most love the look of soul sand in it, and least like birch trees.
Glimmers steampunk one somehow misses the mark for me slightly. I think it's just for the early parts of the game I don't like it as much.