Which Place First Belgium or Holland

See which airport has the best flight options and prices. I don't think it really matters where you start.

I agree with Laura. If you are looking at flights to Brussels and Amsterdam only, I would check the open-jaw options, but I think it's just as easy to round-trip from one airport. The two cities are 2 hours apart by train. Most (all?) of the trains in fact stop at Schiphol on the way. I've never flown into Brussels, perhaps someone else can tell you about that.

I agree, it doesn't matter where you fly out of (Brussels airport is easy to navigate, the train pulls into the airport station), but make sure you visit Belgium last so you won't have to carry around all the chocolate you will buy - or be tempted to eat it all before you get home.