Well, that's odd. Why were the default options for Intellisense turned off when I did a fresh install of Visual Studio 2010 RC1?
Because VS2010 is AWESOME. That's why.
In my installation of VS 2010 this options are enabled after a clean install.
I just posted about why this happens: weblogs.asp.net/.../no-intellisense-with-vs-2010-rc-and-how-to-fix-it.aspx
Hope this helps,
I saw post (somewhere) that if you use reSharper or such tool they set the options off so they can handle it. If your install pulled settings from your vs2008 install they are probably turned off there.