My wife and I both work, combined gross income is about $85,000. What allowances should we put on our w-4? I was thinking of having her put 0 and I would put 2. Thoughts?

Allowances/exemptions go away for the 2018 year.

https://www.irs.gov/newsroom/updated-2018-withholding-tables-now-available-taxpayers-could-see-paych...

The best way to determine this is to use the W4 and estimated taxes section of TurboTax.

To get there 

1.  Click on Federal 
2.  Other Tax Situations
3.  scroll down to Other Tax Forms 
4.  click on Form W-4 and estimated taxes. 

  It will walk you through adjusting your withholdings from there.  As noted above for the 2018 there are tax law changes that will void the exemptions, however you can still adjust the dollar amount you have withheld.