Speaking as a confirmed fabriholic - and with stacks of fabric on hand -
If I was going to do it again, I think I would (mostly) stay with buying fabric only for a definite project in mind - maybe a little extra of each fabric called for -
You will soon have enough leftovers to have a stash going - and if you tend to buy only one "type" - they will go together well enough
That said - the yardages suggested by the other posters are very sensible.
I think fabric breeds fabric, and it soon takes over the house.