Bonds

http://www.mitbbs.com/club_bbsdoc/Bond.html

http://www.mitbbs.com/clubarticle_t/Bond/31335339.html
http://www.mitbbs.com/clubarticle_t/Bond/31335343.html
Or look for kicker bond with higher yield to call in this low yield market
http://www.mitbbs.com/clubarticle_t/Bond/31335637.html

I do not have any muni bond fund/ETF because the interest risk is too high.
For bond fund in 401k, I recommend LSBDX or LSFIX or MXLMX, Loomis sayles 
bond fund or fixed income fund. They are multi sector bond funds which go up
with equity like stock or junk bond but down side risk is much smaller. 
Both have very good return in any 1,3,5,10 year period. 

By carefully choosing individual bonds with higher yield and shorter term, 
the interest risks are much smaller than bond fund or ETF. Kicker bond 
without call protection but yield to call is higher than normal bond, no 
risk if the ask price plus transaction fee is lower than call price, usually
$100. For example, 092840GQ4, 5% federal tax free interest, maturity date 7
/1/2018, bought at 99.92$. My tax free muni bonds have 4-6% yield (6-9% 
taxable equivalent yield) with average term less than 12 years, no bond fund
or ETF can beat that. My taxable bonds have 5-8% yield with term less than 
7 years, and for munis, most of them are insured by AGM or MBIA. For 
corporate bonds, I like falling angels best. Buy them for better liquidity 
than muni bonds and sell them when crisis is over, such as ILFC, AIG, BOA in
2009-2010, Jeffries in 2011, GNW, MS in 2012 and BBY, Dell this year. For 
bond funds, only multi sector or emerging market is useful like Daniel Fuss 
bet Ireland bond last year. Other than that, I think most of us can DIY 
individual bonds with higher yield (not junk bonds, but lower investment 
grade, especially muni bonds with insurance) than normal bond fund or ETF, 
so that the interest risk is much smaller than bond fund or ETF which 
usually put too much weight on treasury bonds, agency bonds, high rating 
investment grade bonds that are most sensitive to Fed rate, and yields are 
too low to offset the risk even you hold them.

For Roth IRA or IRA, mREIT like Agnc, BDC like Psec are good choice, 
currently study MLP like NTI and ALDW in taxable account.