During the establishment of the Empire and the rise of the Rebellion, were there any important (populous, wealthy, and/or strategic) planets which were neutral, meaning not nominally part of the Empire? For example, any planets not formally part of the Old Republic would therefore not automatically been part of the Empire, though presumably some were conquered.
According to Wookieepedia, even Hutt Space was annexed by the Empire.
As described in this answer, there are LOTS of worlds in the Star Wars galaxy, and only a fraction were part of the Republic or the Empire. Did any Core worlds exist outside the Empire or was the heart of their space incontestably theirs? What was the closest non-Empire aligned world to Empire space?
Chiss Ascendency; Empire of the Hand (quasi-neutral); Hapes Cluster; Vagaari Empire (weak). There were, of course several sectors that the Empire maintained only a token presence in that never joined the Rebellion.
– The Fallen Mar 30 '13 at 15:12