Ok, the gold colours and the indian yellow are all really similar - at least they seem so looking at them in the pot. They might be different in use, I haven't had chance to use all the colours yet. But I'd say it probably makes sense only to get one type of gold - they are all nice though.
Also I expect you can have fun mixing colours together too - they seemed to blend together nicely. So maybe a red, blue and yellow would offer up lots of colour-mixing opportunities if you're on a budget.
Or just go old-skool and plump for the colours that you like! That tends to be what I do with these things!