05 Roth IRA Contribution

[icetonez]

I am starting to do research on what I will be doing with my $4000 contribution to my Roth IRA. I currently have $9500 in there and it is about 50/50 VFINX and VTSMX so it's currently 100% equities. Although I am young (22) and should invest a lot in stocks, several investors whose opinions I value (including several on this forum) believe the market has a good chance of declining significantly before it goes up again. Therefor I would like to diversify a bit with my next contribution. Would putting that money in either a bond fund or a real estate investment trust fund be good diversification choices to go with my vanguard equity funds?