If I'm reading this right, its about what do you want to do with the "extra".
If it were me, I'd open the account with Vanguard and split it between VTI, VO, and VB. VTI/VTSAX is heavily weighted towards some of the largest companies, I like the additional diversity and potential for slightly better returns when you include more small/mid-cap companies. VO and VB also throw off less taxable income in dividends per year.