Ha, that's an easy one... in my accessory box, the invisible zipper foot is king! My absolute fav is the Bernina Invisible zipper foot--perfect zippers EVERY time. Pfaff's pulls a close second! --Great foot for thought April!

Hi Ladies, sorry that I'm late to the party...
Here are a few tidbits that might clear up some of the confusion. I used a sewing machine with embroidery capability to do these buttonholes.

The design I used incorporated a standard buttonhole with a mini embroidery. This design was included in my embroidery software program. I noticed that some of you mentioned embroideryonline.com. (They do have a great selection of buttonholes combined with embroidery motifs to choose from and you can just buy the single design you're looking for instead of a whole collection.)

You can embroider around an existing buttonhole--print out a template of the embroidery design that you would like to use and mark guidelines to get perfect placement.

I used a simflex ruler to mark the starting position of each buttonhole. You can do this just as easily with a ruler. I prefer having the flexibility of adjusting the arms of the simflex so I can play with the spacing.

Stitching buttonholes on knit fabric is tricky, especially if you are trying to use a standard satin-stitched buttonhole. Most sewing machines have "Knit" buttonholes which are actually a series of xxxxx instead of a zig-zag. They work much better on knits because they stretch with the fabric. Another tip would be to use a fusible interfacing behind the buttonhole (Fusiknit for example. You can find it at your local sewing super store or at www.sewtrue.com)