The program you use depends on exactly what you want to do. If you're just looking to do a 2D sketch, then AutoCad will work fine. I've never heard of virtual gibbs....no idea what type of program it is. If you're looking to do a full engineering design, then you probably want to use a 3D CAD software like SolidWorks, Pro/Engineer or Unigraphics. I know that Cannondale uses Pro/E. Shizzle is absolutely right about a steep learning curve though. All of these programs are ridiculously expensive too. If you're a student then you might be able to get your hands on them for around $300, but if not then its more like $3000 or more.