Re: Foreign investments or not?
For a while I had nearly all my tax-deferred nest egg in the Vanguard 500 Index Fund (VFINX). I wanted some exposre to the smaller stocks, so now I'm adding to the Vanguard extended market fund (VEXMX, basically a representative sampling of all stocks except the S&P 500). I'm trying to build up the mix to match the total market, which you could also do by picking Vanguard's total market index fund (don't recall the symbol), but I don't have the total market fund available in my 401(k) so I have to mix the 500 and 'not 500' to emulate the total market. I'm satisfied that is enough equity diversity for me.
I heard some of the same advice you did about international investments, and for a while I had some money in an international fund. I pulled it out because 1: it was performing poorly and 2: I didn't understand it. I decided I'd better keep my money where I understand why and how it's invested. I still have a lot to learn about U.S. investments, so for now I'm quite happy having no international equity exposure.
The standard advice applies, of course, about a mix of equities, securities and cash equivalents based upon your investment time horizon. I'm assuming you've considered that.