The best props I have found and used are 9" carbon fiber ones. I have ordered some from DSLRPros.com, and have also found the same ones, just a lot cheaper on ebay. The ones I found are made by gemfan, but they could just be relabeled. I've used silver tops, and the magenta tops. There is a noticeable difference in overall speed and response. They also hold up better against minor crashes. The carbon fiber props may chip and fray a bit, instead of exploding upon impact like the plastic/stock ones.
Here is an example:http://www.ebay.com/itm/8x-Carbon-Fiber-9-9443-Self-Tightening-Propeller-Prop-CW-CCW-DJI-Phantom-2-Ver-/121418612111?pt=Radio_Control_Parts_Accessories&hash=item1c451cfd8f