For a DD, it is nice to get a system with a front track bar and some sort of caster correction. Just springs will make it a little light on caster.
We like people to start with the 2.5" Flex System and then gradually build up to a 2.5" Max. Travel System. They are pretty sweet.
Hydro or Nitro white bodied or black bodied shocks are not part of our game plan. We prefer to start you out with something like the bilstein 5100 with internal floating piston and go up from there.
It really comes down to your budget and your needs. We like to start with quality parts that you can expand on as your needs/desires progress. It happens, trust us.
Tera's hard parts are nice to build from as well. We would just prefer some progressive rate coils and the 5100's to start out with, but that is not for everyone's budget.