Edimax EW-7811Un 150Mbps 11n Wi-Fi USB Adapter - $7
Setting up the Raspberry Pi was a breeze. The only snag came when I tried to configure my wifi dongle with my wifi network settings. My router, a Netgear N900, is setup to use WPA2-PSK with AES encryption and after trying out a few things as suggested by multiple blogs, none of them worked... until I came across this:
The configs below also set a manual IP at 192.168.1.60.
iface lo inet loopback
iface eth0 inet dhcp
iface wlan0 inet manual
Then I installed wicd and wicd-curses with the following commands:
sudo apt-get install wicd
sudo apt-get install wicd-curses
Run wicd-curses at the command line and setup your wireless network and let it automatically connect to this network on startup.
Reboot and I was able to connect to my wireless network.