The slug is real nice. Mine runs debian-arm which has quite a repository for precompiled packages.
The slug does not have a graphics card. This is just fine, because you can forward an X.org session to another machine via ssh to do your patching.
The slug does not have a sound card. There are packages on the repo to support ALSA and maybe Jack?? Pd needs to run with a floating point emulator to do any audio as well...
I'll tell you, I originally intended on using the NSLU2 as a way to encode wah pedals and make an OSC/UDP stream. That way, you could "spread the load" across a network of specialized devices: Arduino does ADC for sensing, the NSLU2 (build orifinally as a network device, booting from flash) builds the network packets, and a machine with powerful processors/GPU and a nice DAC does the audio and video. Maybe I'll revive the project once I build a new 'lab'...