Last week, for a friend's party I did a spot of DJing and VJing using MC and G-Force. I played some ambient/chill music to start with, then a friend did a live set. I used MC & G-Force to start with, and G-Force to accompany the live set.
Pictures are here:
http://public.fotki.com/gpvillamil/japan/kaon_bloom_party/Things worked really well - I had an ATI Remote plugged into the laptop, so I could actually wander around and mingle while still being able to control the music & visuals. I will be investing in a computer controlled mixer from M-Audio to allow for better integration with other audio sources.
It would take a tiny additional effort to use MC multi-zone functionality to add a headphone monitor function to support live DJing.
The SB4.1 skin from Cascius was perfect - fit right in with all the DJ gear.
This is me on the left:
http://public.fotki.com/gpvillamil/japan/kaon_bloom_party/img_7398.html