Building a computer- compatibility questions (stuff physically fitting)

I plan to build a computer in the near future. I have watched several helpful videos, so I am knowledgeable about all the different parts and what to look for. However, since I like to think ahead, I have a question. Do I need to be worried about stuff physically matching up and fitting together? The two things that I immediately saw was the motherboard backplate and the motherboard itself. Do I need to be picking out a specific case that will have the motherboard screw holes and backplate cutout in the right spot/size, or are they all universal?

Maybe I am "stressing out" over nothing, but it is something I was wondering about.

If you get an ATX case, you'll be compatible with almost everything.
Once you select all your parts, post them here with links and we can verify compatibility.

Thank you for your response. I will post again once I select parts.

PS- I am currently working with Windows PE at my internship, so I checked out the link in your sig. Very helpful.

Post a list of what you are thinking of buying here, with links and we can double check. There are a few things you have to be sure of, like socket size of the CPU and motherboard, some of the really big graphics cards can have fit issues with some of the smaller cases, but for the most part this is not too big of problem.

Thanks to a fairly complete set of standards, it would be difficult to build a system with incompatible parts. You get an "ATX" case, power supply, and motherboard and make sure your motherboard and memory are both DDR3. Make sure your motherboard's CPU socket matches the socket type of your CPU.

All fairly straight forward stuff.