my vanilla vista premium install has the windows tree consuming 7.5gb. office 2007, adobe, and a few other apps have the programs tree at about 2.5gb. so, i think 15gb is barely adequate once you start adding documents.
I want o create a dual boot for XP and Vista. I will use a partition manager to divide up my 160 GB hard drive. I understand that as a minimum Vista needs 15 GB. I also read somewhere that for performance reasons you should allocate 40 GB for Vista. Is that much necessary? For performance and my small install of programs (compared to some people) what is the best size? I will use a third partition for backups, ISOs, etc. Any input will be appreciated? Thanks in advance.