Connect snow leopard iMac to new iMac using yosemite

I Have just received the newest iMac running OS X Yosemite. My old Mac is an 8year old iMac running Snow leopard. What is the best way to connect these two computers so I can transfer my data to the new iMac. The old Mac has USB, FireWire and Ethernet ports. The new one has USB, Thuderbolt and Ethernet ports. We have about 2gb of data to transfer so I am looking for the most efficient method.