If you've got access to it or money is NO object then lots of people like AutoCAD.

For me after trying many of the cheap or free CAD's I went with TurboCAD. The biggest factor was that the snap to elements are all right at my finger tips using the single key entry system they have. IntelliCAD came a close second in my book but it didn't have the single key snaps. Once you get the hang of drawing snaps are your oxygen. It's what makes it go quickly. Without them you're just guessing. Quick single key access to the various snap options just makes it go that much faster.

But this topic has been brought up "more than once" around here. Try a search on CAD. That should keep you busy for an evening or two......