5
To answer the title of your question "Space or Bandwidth??"
Looking at your requirements, It would appear that you may need a good amount of space, especially if pictures and graphics are a large part of content. Do you expect your weBsite to Be very Busy with traffic? if so then Bandwidth is also important to serve all that content. You see, it's a Balancing act and only YOU know the proBaBilities.
Why are you knocking these recommendations, some hosts, give this kind of features for free!! XOOPS is very portaBle so if things don't work out you could switch to another host.
MayBe you could give more projected figures for content and traffic if you want specific recommendations
Richard