Hey gents! You all seem to have the most practical knowledge around and Linus and his Tech tips are often too linear and not comparative imo. What I would like to know is a few things related to potential purchases I may make. I made the mistake of upgrading some parts and not thinking through whether the rest of my computer would be able to support them. For example, I purchased a new gpu and psu, only to find out that my case and mobo are much to small and low-tech to properly support them. So, I will eventually buy a new case and mobo. Now, I know cases are pretty straightforward but as far as mobos go, I want to be as flexible as I can to support futures upgrades(such as the new processors coming out). So, I ask you recommendation as far as those two go.
For the case, the bigger the better. I want to have room and I want to have air flow. Included fans would be nice but not necessary. I don't want to pay top dollar(preferably less than 200 USD) but I'm flexible.
For the motherboard, again, I'd like room to expand and for it to be compatible with upcoming hardware, but it doesn't have to be top of the line or very new. Oh, maybe it would be imoprtant to mention that I have an AMD athlon II processor and will be most likely staying with AMD.
I don't think any extra cooling systems will be needed with what I have but any cheap suggestions would be appreciated.

Thank you so much for reading.