Based purely on what I expect the ships to go for, most of them being in the $20-35 range...

1 Core set

2 Gladiator SD's

1 Assault Mk II

2 CR-90's

2-3 fighter squads for each side, depending on what comes with them.

I think that would give the most list building possibilities and still be in the budget of what I'm willing to spend at this time.

I think 1 VSD and 2 Gladiators would allow for more options then 2 VSD's would. But I could see maybe picking up a extra VSD at some point.

Same goes for the MK 2 vs a 2nd Nebulon B.

I honestly don't see the need for a 2nd core set... If the core set ship expansions have different upgrades, then the core set then a 2nd core makes even less sense. Especially since you can at best use 3 VSD's in a list, and that would likely leave no room for the Gladiator...