Charts after the jump.
Here's the chart from Amazon's
Alexa service:
Alexa's methodology is suspect, however, because its sample -- the millions of people who download their toolbar -- is self-selected.
Sitemeter, on the other hand, provides hard data:
That chart is for Daily Kos. Unfortunately, Instapundit's charts don't load. [Update: Apparently this is just a problem on my end.] The only long-term numbers I can find for comparison are this week's numbers, which isn't a fair match-up. But based on the last month's worth of data, SiteMeter projects dKos will receive 4.27 million visitors next month, while projecting only 3.87 million for Instapundit.
The popular blog rankings that track incestuous activity rather than traffic, such as Daypop and the Ecosystem, still rank Instapundit above dKos, however.