For integrated terminal use Ctrl+`
From the release notes:
With the May release, we are rolling out the initial version of an integrated terminal. You can open the terminal using Ctrl+`, from the View | Toggle Integrated Terminal menu, or from the View > Toggle Integrated Terminal command in the Command Palette.
https://web.archive.org/web/20160616204248/http://code.visualstudio.com/updates/#_workbench (the 1.2.0 May release in 2016)