The fed is propping up the market- we already know that. The question is: when does it end, and how far and how fast does the market decline once that inevitable event takes place?
One thing that concerns me is housing.
Price of housing- about twice the median income. Oh, I know it's not right now. But that's the actual price. Ordinary interest rates are historically- about 8%. Housing price v. median wage:
1950: $7354 / $3,319 =2.2
1960: $11,900 / $5,620 = 2.1
1970: $17,000 / $9,867 =1.7
1980: $47,200 / $21,023 = 2.2
1990: $79,100 / $35,353 = 2.2
2000: $119,600 / $50,732 = 2.3
2010: $170,500 / $50,221 = 3.3
I do recognize that there's something to be said for locking in a low interest rate mortgage right now and that paper losses notwithstanding, you pay roughly the same, and you end up with a house valued about the same whether you buy a $300K house at 4.5% or you buy a $150K house at 8%-- even if the market plummets 50%. So, interest rates (if they're long-term, and fixed) are definitely a consideration.