I would like to begin testing and working with BackTrack.  I have heard that the <a href="http://www.alfa.com.tw/in/front/bin/ptdetail.phtml?Part=AWUS036H&Category=105479">Alfa AWUS036H</a> wireless adapter works well with BackTrack and allows for packet injection.  This adapter, however, is only a wireless b/g adapter.  I was curious if there was something similar to this adapter that would allow for packet injection, work on Windows and Linux (especially BackTrack), and would support wireless b/g/n?  Support for wireless a would be a plus too, but not a requirement.  Also, are there any replacement antenna's that one should consider using with this device?