I was going to get the EM406 1HZ GPS for $60, but saw that this d2523t 4hz GPS is only $20 more. I see that it has a similar connection, and output. I don't know if it will work though, can someone verify weather its compatible?
I suggest you save up $50 and get uBlox & interface board w battery backup from Jordi, waiting for a fix after a power down is a pain, and you will get better performance & longer life, the EM 406A is OK, but uBlox is designed to provide aeronautical solutions, 406 is for boats /autos.
I love my 406 s, I still have my first one and have retired it and plan to put it on the wall in some sort of frame or art installation!!
For me that sandy square represents the start of the adventure, mine was from Eladio and drove an RCAP3 recently it has been connected to an Xbee for tracking duties and now as I say it sits in the draw waiting to become part of a history wall!!
Ublox is the way to go, but a 406 will more than do to start.
You get out and start flying, and then fly some more. Lots of people here add expensive bits fiddle about with cameras and fly once in a blue moon.