AP works well, as does a blend of 4 parts AP to 1 part cake flour.

I also use all-purpose flour with great results.

We use regular all-purpose flour with fabulous results. It may not be completely authentic, but it tastes great! Here's our recipe and some pasta tips: http://romeocucina.blogspot.com/2011/01/homemade-pasta-fun-for-entire-family.html. Good Luck!