Hi all -- Thanks for the advice above. To answer the question about timeframe, definitely at least a few years. I have no reason to need the money in cash within three years, and realistically probably not within the next five years. Not sure where that places me on the risk-aversion scale, but I guess it means I can tolerate some ups and downs.
On the question of taxable vs. tax-deferred accounts, I guess I'm talking only taxable investments here. I'm maxing out my 401K (actually it's the Thrift Savings Plan since I work for Uncle Sam), so I'm getting the maximum tax deferral there. A follow-on question to that: in 2013, the maximum contribution to a tax-deferred 401K (or TSP) is $17,500. Does that mean I'm not eligible to buy any other such funds like a Roth IRA or Traditional IRA? Sorry for the dumb question, but I'm not up on the rules for this stuff.
Bottom line is, I really feel like that money's just wasting away in my ING Savings account, earning only 0.80% right now, and I can risk it in order to grow it. And thanks for the link to the MMM article. Been reading this blog voraciously since I discovered it a couple months ago, but somehow missed that particular piece.