My data source for this chart is the Excel file accompanying the BEA's latest GDP news release(see the links in the right column). Specifically, I used Table 2: Contributions to Percent Change in Real Gross Domestic Product.
Over the time frame of this chart, the Personal Consumption Expenditures (PCE) component has shown the most consistent correlation with real GDP itself. When PCE has been positive, GDP has been positive, and vice versa. In the latest GDP data, the contribution of PCE came at 1.05 of the 1.54 real GDP. This is a downward revision from the 1.72 PCE of the 1.96 GDP of Q1.
Note: The conventional practice is to round GDP to one decimal place, currently at 1.5. The 1.54 GDP in the chart above is the real GDP calculated to two decimal places based on the BEA chained 2005 dollar data series.
For a long-term view of the role of personal consumption in GDP and how it has increased over time, here is a snapshot of the PCE-to-GDP ratio since the inception of quarterly GDP in 1947. The Q2 2012 ratio is 70.7%, a bit off the all-time high of 71.2% in Q1 2011.
I'll update these charts when the Q2 Second Estimate is released.