The measurement of the flux of low energy Solar neutrinos will probably be crucial when it comes to solving the Solar Neutrino Puzzle. I will argue that future experiments dedicated to measuring 7Be neutrinos (Borexino and possibly KamLAND) should be able to establish or exclude Vacuum Oscillations (via seasonal variations) and the LOW MSW solution (via the Earth-Matter interactions).
Furthermore, future experiments that intend to measure the pp-flux (such as HELLAZ) should be able to directly determine that active neutrinos other than electron-type neutrinos are coming from the Sun.