I really like Iridescent Gold. It's great for when you want a subtle hint of shimmer, and it pretty much goes with anything.
I also love a good brown mist, such as Suede or Coffee Shop. Brown is another neutral that will accent anything beautifully.
Those would be good, versatile, sort of neutral ones to start with. I also LOVE Patina and Candy Apple Red for pops of brilliant color.
These colors are the ones I use the most.
Hope this helps!