Allocating 10% bonds could be extreme (age 50-60) or reasonable (age 20-30). It also depends on when you plan to retire, with 10% bonds being appropriate for decades away from retirement.
You suggested $50,000 invested at Vanguard. I'd suggest dividing that so you're comfortable with each chunk, and plan on investing regularly until you've bought it. Something has you waiting on the sidelines already, so getting started is very important. The question is would you invest $25,000 at once (2 chunks)? Or $10,000 (in 5 chunks)? Pick the amount you feel comfortable investing at once, then keep doing it.
Vanguard has lots of low cost funds, and it's hard to make mistakes there. I'd definitely go with Vanguard. You can also find low expense ratio funds at Schwab or Fidelity, but they are mixed in with expensive, active funds.