These look like very powerful machines, but if I get one, I will need it to last me a while like 2-7 years, what would be the minimum specs or processor that I could do heavy video & editing of RAW photos, graphics etc without problems? they are expensive & notice that they seem to be highly expandable, so was thinking I could get a more base model & add things as I need them. Would a 4 core work for me? or should I go for more cores? will there be a refresh of these as well? I dont want to get a previous model only for drastically new better model to come out. I notice the mac pros now do not have the new thunderbolt port on them like the macbook pros. Any input from experienced users who do video & graphics input would be appreciated, thanks in advance new to mac pro.