I got Pre-Design2, many years ago to help with digitizing my embroidery. However, I've discovered that it works great for my computer quilting designs. I've never upgraded, but the newest version is
http://www.pre-designstudio.com/
Allbrands sells a previous version
http://www.allbrands.com/products/abp03211.html
The advantage is that the lines do not need thinning and it is very easy to change different sections of the design before importing it for quilting.