Is it important to match colors of hardware? Also should I get a window case or non window?

Solution
The color has no bearing on the quality or the performance of your parts. Some people prefer their PCs to also be fashion statements; that's fine, but does not make them any faster, or "better" in any way. By all means avoid a color you think is ugly, but it really doesn't matter. If you like your particular colors, then you may well enjoy having a windowed case, especially if you have also added LED lighting of some kind to your case.
This is not to disparage a neat, well-thought-out build, although IMHO, neat cable management is more impressive (and useful, as airflow is better) than particular color choices.
The color has no bearing on the quality or the performance of your parts. Some people prefer their PCs to also be fashion statements; that's fine, but does not make them any faster, or "better" in any way. By all means avoid a color you think is ugly, but it really doesn't matter. If you like your particular colors, then you may well enjoy having a windowed case, especially if you have also added LED lighting of some kind to your case.
This is not to disparage a neat, well-thought-out build, although IMHO, neat cable management is more impressive (and useful, as airflow is better) than particular color choices.
 
Solution