Currently Being ModeratedJan 30, 2013 8:58 AM (in response to frosales)
Applications do not take up that much space. Here is a partial list of apps on one of my computers:
And there is more. This Applications folder is about 20gB. There are other files that come with these programs, but they take up much less space.
In sum then, you will be fine with 250 gB, of which you will take away say 30 gB for Parallels and its contents.