I may just be excited that I've finally found a way to do this, but in the off chance that anyone is still using foobar2000 and interested in having pretty colored pixels move to their music on their PC, here is how I got milkdrop and other nullsoft visualizations working with foobar2000 seamlessly. Its a truly great thing to have for a windows based htpc and is part of many htpc packages like XBMC. Now you can have the sound quality and the visualization together.
If you haven't heard of milkdrop before, it is a highly capable visualization with literally hundreds of different presets out there for it. I really missed this visualizer when I switched from Winamp to foobar2000 for better quality and less bloat years ago and works well with multiple monitors. I've tested this myself on XP pro and Windows7 64.
First, you need to download the foo_vis_shpeck wrapper plugin and extract it to your foobar2000/components directory in your program files (C:\Program Files or C:\Program Files(x86) if you have 64 bit).
Download here: http://yirkha.fud.cz/progs/foobar2000/foo_vis_shpeck-0.3.7.zip
Second, you need to download the dummy Winamp directory from here and extract it wherever you like (I put it in the foobar2000 program directory). You may need to download 7zip extractor to extract the files.
Download latest here: http://www.mediafire.com/?ybv4a39yrp4l15m
Now start foobar2000 and enter preferences. Configure Shpeck under the visualization section by setting the directory you extracted your winamp dummy dir to and then select Milkdrop in the list of available plugins and click configure. I set my default to fullscreen, set my fullscreen settings to my desktop resolution, and, since I have a faster video card and cpu, I upped the mesh size under more settings to 96x72 (completely optional, but looks amazing). I also set a keyboard shortcut to my M key to start the visualization while in preferences.
If you want to see the options in the visualizer, you can push the F1 key to see a list. :)
Credit goes to Yirkha on Hydrogen audio forums for creating the shpeck plugin and Nullsoft for making the visualizations available freely.
Edited by manaox2 - 6/4/11 at 10:44pm