It depends on what you are looking for regarding performance. For outright pull, the APC 11.5x4 or 12.25x3.75. For response and willing to sacrafice some of that pull, run the 11x4 or 12x4 Brodak Y&O (wood), or run the Zinger 12x4 modified, if you're willing to sand on some props for better performance (refer to thread on Props).
Hope that this helps!
Kevin