I suggest using Unleashed pack.
Enable the Biomes o'plenty because they're cool.
Unleashed has stuff like advanced solar panels, dartcraft, gravi suite, apm...
If you decide to use Unleashed pack, enable all mods but
Death timer(annoying, i've lost some good stuff because it left the chunk loaded)
Vending(up to you, but i've heard it's bugged. Could be cool for trading though(
Nether ores(bugged i think + noone really needs those + they're potentially explosive and Pigmen don't like you mining them)
Not sure if you've already made changes to mystcraft config, but it's probably good to disable cave worlds, meteorites and any other bad effects that cause massive lag.
EDIT: it also doesn't have Gregtech.
See you online if you decide for Unleashed
