Dow Industrials edging toward all-time high
The Dow Industrials came within two points of their all-time high today, and the S&P 500 began to test the bounds of P/E-based "fair value", skittering just above the long-term average price-to-earnings ratio for the broad large-cap Index.

From the old Fed Model perspective, US stocks still look extremely undervalued compared with US bonds, but the Fed Model broke when low inflation and the intervention of foreign central banks began pushing medium-term US Treasury yields down.
On the topic of Treasury yields and the famous curve that charts those yields across the range of maturities, the Dallas Fed has some interesting thoughts (via Economist's View)
I should have the year-to-date asset class returns updated shortly after month-end. That will provide even more perspective on what's happening in the race of returns between stocks, bonds, and other asset types.
As Negativland advised, shop as usual and avoid panic buying.