The proposed Planetary Science budget from 2011 to 2015 includes a number of lunar science missions. The Lunar Quest Program funds LADEE (Lunar Atmosphere and Dust Environment Explorer) and the ILN (International Lunar Network). It also funds Lunar Research and Analysis. The LRO (Lunar Reconnaissance Orbiter) now orbiting the Moon is scheduled to be handed over to the Lunar Quest Program later this year. The ILN is currently under review by the Decadal Survey process because of cost reasons. According to Future Planetary Exploration blog, the Decadal Survey is also considering a Lunar Polar Volatiles Lander.
The Discovery Program is managing GRAIL (Gravity Recovery and Interior Laboratory), and one of the 3 finalists for the next New Frontiers mission is MoonRise, a lunar sample return mission.
The Lunar Quest Program has a relatively small budget - not much over $100M per year. That makes sense because this program is focused on small, affordable missions and research. Considering GRAIL, and assuming Moonrise wins New Frontiers and ILN or some mission to replace it is funded, an appropriately strong lunar science program to set the stage for the Flexible Path to the Moon would exist. However, there is no guarantee that this will happen.
Noting that the Mars Exploration science budget is about $500M per year, if the Flexible Path to the Moon is to be implemented, it seems appropriate to considerably increase the Lunar Quest Program budget to allow more small lunar science missions, or to start a separate line of larger lunar science missions. This would ensure a steady series of lunar science missions appropriate for the Flexible Path to the Moon. In the near term, this might come at the expense of other planetary science missions, but the capabilities developed along the Flexible Path to the Moon should in the long run build a strong foundation for more cost-effective and ambitious science missions across the solar system. The short-term effect on other planetary science missions might not be great anyway; GRAIL is already funded and it's possible that MoonRise will be funded too. This change simply ensures that a steady series of lunar science missions is funded to help pave the Flexible Path to the Moon, and to set the stage for more detailed lunar science and development when astronauts eventually reach the lunar surface.