The tax implications are something you'll have to determine for your particular scenario.
In general, things that throw off lots of taxable events without creating income are usually best kept in the tax deferred area. TIPS, REITS, high turnover stock funds and commodities funds create lots of low predictability taxable events...in the case of TIPS you dont even get the income until the bonds mature.
Low turnover index funds (one does not automatically mean the other...there are high turnover indexes) sit well in the taxable portfolio.
But heres the part YOU have to do...somewhere along the line you have to drain off the money you're going to live on. If those are long term capital gains from stocks and stock funds, that will be ok to have in your taxable port. If its short term gains, those could get to be rather expensive. If you have a lot of trailing capital losses to offset gains, a wild and crazy set of stocks and funds in your taxable port might be just great. Dividend and interest income from bonds, MM's and CD's are taxed at your nominal rate.
For my situation, I have no debt whatsoever, and complete control over my withdrawal rate. I live very nicely on ~30k a year but could live comfortably on half that. My taxable portfolio throws off enough dividends to cover most of that and I'm hauling along ~$110k in short and long term capital losses from a few years ago to offset any capital gains. The low withdrawal amount coupled with good deductibles and my carryover losses means I havent paid taxes in a while and wont for some time. My taxable portfolio is very conservative, somewhat like your overall port is. Its conservative because with a low withdrawal rate, I dont have to take any risks and if theres no need, why keep yourself awake at night? On the other hand, since I wont be tapping my IRA for 20+ years, I put emerging market stocks, reits, healthcare, energy and other volatile rocketships that do well over long periods of time in that area. In a perfect world, I ride through the next 20 years with my primary taxable portfolio largely intact, having lived off mostly interest/dividend throwoffs, and my IRA will have appreciated significantly, assuring me of a very comfortable 'real' retirement should I live a long time...and thats what I plan to do!
But without a comprehensive view into your financial situation, neither I nor anyone can give you any exacting suggestions or advice.
The real keys for you are controlling expenses and withdrawals, the right tax strategy for the long haul, and exactly how much risk you're willing to take in this endeavor over the next 40 years.
My last suggestion is if you're single, go marry a nice woman with a job!