Best practice for hardware upgrade

Hello

it is time for me to upgrade my badget pc especially to improve support for HD video, video editing and make it less noisy
In fact I have a dell dimension 4600 that is nearly 10 years old.

I see two challenges here:

1) identify the minimum requirements to run the applications
2) identify the hardware component that are supported by ubuntu

For instance I just entered a shop in town and for budget pc they proposed me the Asrock motherboard G31M-GS R2.0 with Dual Core Intel cpu. However this was suggested assuming that Windows 7 would have been installed. To ensure a successful upgrade of the main hw components how do I know this will be fine with Ubuntu?

it would be useful to know any best practices about all the above aspects

thanks
Franco