Bill, in your case, since you are very experienced with 2D drawing, you might want to start out with a 2D CAD program and work up to 3D later. Before I get started, allow me to tell you how I came upon this knowledge.
My Background with CAD
I took drafting classes in high school, learning how to do standard drawings and isometric drawings the old fashioned way - using pencil and paper at a drawing table, with a drawing board, T-square, triangles, French curves, lettering guides, and various grades of pencil. We even did drawings on blueprint paper and blued them the old fashioned way using ammonia. Those were the days!
As time went on I ended up with a computer and decided to purchase my first CAD software, called KeyCAD. I found it very easy to use, and it was fine for simpler drawings. The tools it had were somewhat limited, but it worked well for my purposes. After a few years I upgraded my computer from Windows 3.1 (yes, in the computer world I would be considered ancient) and I had to find a newer version of KeyCAD that would work on Windows 95, but there was no such thing. KeyCAD was no longer available. During this time I also had the opportunity to try TurboCAD, which my employer had on one computer. I tried it but did not care for it, though I am not entirely sure why anymore. I finally stumbled on a product called QuickCAD at half the cost of TurboCAD, so I gave it a try. It took some time to get used to it, but it had greater capabilities than KeyCAD and over time I came to like it. It also had the ability to read and save files in multiple formats such as DXF and DWG as well as its own native CAD format. In time I had to upgrade again, and by this time Autodesk had purchased the company that produced QuickCAD, so the first that happened is that the price went up - by about double! Oh well, I bit the bullet and upgraded without problem or fuss and over time I had to upgrade once more, but QuickCAD was no longer available!! Some careful research revealed that Autodesk improved the product and re-released it as a product of their own called AutoSketch. I purchased a copy of it, eventually upgrading to the last version of that product, version 9, which is what I still run today. Long story short, I've been through several iterations, versions, names, vendors, etc., and have come to accept the fact that upgrading and software changes are just a part of life.
Through the years I have also had the chance to try other CAD packages. I mentioned TurboCAD, which is still around today. It is also most likely the software that I will purchase next time as Autodesk has also discontinued AutoSketch. In addition to TurboCAD I also tried Google's Sketchup which is more of a 3D program, and I tried one free package from Dassault (the name escapes me now) but it kept crashing on my computer so I gave up on it. I did briefly (VERY briefly I might add) consider AutoCAD LT but quickly realized that I didn't have pockets that deep, especially for something that I do only for hobby purposes. I also once purchased a piece of bargain software called CADKey (yes, more or less an anagram of KeyCAD) for a whopping $5. It was horrible and I'll say nothing more about it. Let's just say that the CD it came on made wonderful fireworks in my microwave.
So now you have an idea of my experience with various CAD programs over the years. Keep in mind that I am no expert in all the versions of CAD software that are out there, but I've dabbled in it enough to know what to look for.
What CAD software should I get?
The hard part is knowing what program to invest in. The reason I say invest and not purchase is because they are two different things. The cash outlay for the software you choose is but a small part of your investment. The biggest part of your investment is your time. Time to learn the software itself and time to learn how to coax the software into doing what you already know how to do in your head with pencil, paper, and straight edge.
There are other considerations as well, such as how long will this software be around? Will it read and save to standard formats such as DXF or DWG? Will it save to or read them properly? Can it save as a PDF so that I can share my drawings with others but without danger of them modifying my work? How much does the software cost? Is it a one time purchase or does it have an annual license? Will I have to go to school the rest of my life just to learn how to use it, or is it rather intuitive?
So, let's start with some basics.
One of the most important things to consider is file format. For many years now, Autodesk's AutoCAD has been something of an industry standard. AutoCAD stores drawings in DXF format or DWG, though DXF is the preferred standard. If you want software that will be able to open drawing files from other users, you will want something that can handle DXF and DWG files. Period.
The ability to export a drawing as a PDF file is very important to me, maybe not to others, but since the advent of CutePDF and other programs in Windows that can print to a PDF such as Microsoft Print to PDF (included with the Windows OS) it is not a requirement of the CAD software to be able to print or save in that format. Windows can do it for me.
The next question is this: Do I want to draw in 2D? 3D? Both? I recommend finding something that will let you draw either way, but does not lock you into either one. Myself, I have only dabbled in 3D a little bit. All of my real drawings are still done in 2D as it is what I know best.
Cost is a concern for me, but I also realize that you get what you pay for in most cases, so it doesn't bother me to spend a little money. Despite that, I've never spent more than $90 for any of the software that I've purchased.
Once you've narrowed down a list of software packages that you might be willing to try, check out the reviews on them and see what other people are saying. Sales literature will tell you what the vendor wants you to believe, user reviews tell you what actual users believe - for the most part. Even product reviews can be tainted, so be prepared to take them with a grain of salt. Make sure that they have good training materials and videos available, you will need them.
This is a good place to break for now. More to come at a later date.
