I have been reading up on investments and also reading the posts here on this wonderful forum. My question is I am currently maxing out my TSP and started a Roth IRA with Vanguard. I am investing the max 5,000 in the Total Stock Market Index Fund with Vanguard as a Roth IRA. My question is since I am already in the stock market with TSP Funds should i change my Roth and do another type of fund such as a REIT or commodities index, to diversify? I am also not sure what other index funds at Vanguard I should invest in so any recomendations would be appreciated.