I've been trying to get my desktop's wireless adapter up and running after installing the latest stable crunchbang distribution. It seems it should have the ath9k drivers built-in but lsmod | grep ath9k returns nothing. Ethernet works but getting nothing from TP-Link PCI-e wireless adapter.

What does uname -a return?

Linux thornetwork 2.6.32-5-686 #1 SMP Sun Sep 23 09:49:36 UTC 2012 i686 GNU/Linux

That's the confusing thing about Crunchbang. Their 'latest' stable release on the website is ancient - that's why you've got the 2.6 kernel and don't have the latest ath9k drivers - you need one of the backports. Click on the BPO tab on the downloads page and install that, it'll have the necessary wireless drivers baked in.