Video and photo editing

Hello,
I'm looking for advice on building a new system to be used for home video and photo editing, I have mini DVs that I would like to edit and convert to dvds, some internet video streaming so an HDMI would be great so I can hook it the TV.
My budget is around $500 It would be nice if I can add a blu-ray and stretch the budget a little bit maybe up to 550 because i need to but OS on top of that. I have never built one before so every advice is appreciated.