i would only buy 1000 & 5000 chips if my tourneys required them.
how big are your tourneys and what's the initial chipstack? do you do rebuys and addons?
the answers may help you decide how many you will actually need.
if you're gonna get them even though you don't need them, well, you don't need us to tell you how many to get now, do you?

get as many as you want!