welcome aboard ... just a bit of FYI here ... you are about to be bittin by the reef bug !!
in order i would this ...
1. Lighting (depends on what she wants to keep in the tank)
2.
RO/DI unit to make PURE water for the tank. (with a high rejection rate [75gpd])
3.
Skimmer (do not skimp here)
4. Hydor Korallia Powerheads (for water flow IN tank)
5.
IMO a deep sand bed (5+ inches) is a great choice
i would use another tank for a
sump as you mentioned. be careful with sterilite containers, as they have been know to crack under the pressure of water being in them.
