budget htpc and media storage

You can do it but hardware compatibility becomes the issue at some point so you just might as well upgrade to a newer mobo and cpu.. .

You can use what you have..

But when you realize a $33 G540 is faster and uses less energy (much less) you decide you might want to replace it;.

You can get a mobo/cpu/Ram combo for under $100 on current generation platform.

I would say go for it... and upgrade when you feel the time is right. Nothing wrong with getting your feet wet.... It should work