Cards containing the Realtek RTL8187L chipset work quite well and is recommended. The driver patch for this chipset has been continuously improved and quite good at this point in time. The Alfa AWUS036H is a very popular card for use with the aircrack-ng suite.
NOTE: For surfing Internet with ALFA-AWUS050NH on Ubuntu Jaunty with rt2870sta driver, you must use the Kernel "2.6.28-11-generic #42-Ubuntu", without change or updates the drivers modules. NOTE: The tutorial is not related to Ubuntu karmic. Driver RTL8187/Stacks-mac80211 (ref. ALFA-AWUS036h) - These drivers, for surfing Internet, are more stable than r8187, and fully compatible with Network-Manager 0.7 installed by default on Ubuntu 9.04. Network-Manager 0.7 installed by default on Ubuntu 9.04. - Supports all encryption without problems. (OPEN, WEP and WPA/WPA2) - With Compat-Wireless, the "injection" working, but for support “Fragmentation attack” (opt. -5) you need to install one patch. - The RX sensitivity and packets injection is less, related to drivers r8187. Driver r8187/Stacks-ieee80211 (ref. ALFA-AWUS036h) - This driver is recommended for use with the Suite of Aircrack-ng, but not particularly suitable for Internet connections, as less stable and disc...