Like everyone else has said, both are good. Combined they represent over 9,000 stocks. Yes, some might be expensive today. Where will it be in 20 years? Likely up, and likely up a lot.
For allocation: The world is roughly 50/50.
I am 60% domestic, 40% international. There are several good research papers that show this split lowers the volatility of your portfolio more than other allocations. If you are 100% stocks then a 70/30 split accomplishes about the same thing.

source:https://personal.vanguard.com/pdf/icriecr.pdf