The simplest way to switch the screen from the rPi to the desktop would be to make sure the monitor has 1 HDMI + 1 of any display connector that you want to use to connect to the desktop. You can then just use the button to switch between inputs to the monitor. What will be more annoying is switching the keyboard and mouse between the two.
You do not need a dedicated graphics card unless you are planning on gaming at high quality graphics on modern games, rendering stuff, or using intense 3d modeling/CAD programs. You will be able to run desktop applications across multiple screens with the Integrated graphics on your CPU. I really need a good plan to be able to help you. Programs you run daily, stuff you can't run but would like to, etc.
Good Call on the input button. I want to say that I had some kind of connector in the past that allowed me to share 1 monitor, keyboard, and mouse between 2 computers so I would think I could probably find something like that to share keyboard and mouse between the desktop and rPi? Its been YEARS though so I cant remember exactly LoL.
What I can tell you as far as programs I currently use, I would like to be able to take my work home with me from time to time which I use Microsoft Office for. I currently do a lot with Macros in Excel (my plans are to eventually write small web based apps to handle the majority of my Excel/Macro programs). Things like Outlook, Word and such shouldnt really affect anything I assume. I also have Adobe Creative Cloud, although I dont use it to often it and am not that great with it, it is fun to dabble in Photoshop. I know there are also a few programs in there for Mobile App development that might be fun to get into some day. I am pretty bad with having about 10 different windows open at once so im assuming that could affect the RAM / CPU I go with. The only thing I have tried to run on my laptop that really gave me fits was Adobe Illustrator, but honestly I was only trying to use it to open a file that I couldn't open with Photoshop to cut part of the image out and move it over to Photoshop anyways.
With currently reading up on MySQL and PHP, it seems like I will want to install some type of test server on my computer (EasyPHP DevServer is suggested in the book I am currently reading). I am not sure what kind of strain on the system something like that would cause.
I love to tinker and pick up random programs on the way. I was playing with some reverse engineering of mobile apps which required programs like IDA and NetReflector. I recently downloaded NetBeans for playing with PHP. Sorry for making this question so tough LoL
Like I said it has been 10+ years since I built my last computer but thinking back I feel like the Motherboard and CPU need to be top of the line, that you cant really upgrade those as easily as you can do things like add a larger hard drive, extra RAM, a better video card, so on and so forthe?
Edited by bkweibley, 05 January 2016 - 09:09 AM.