zehrila - 7:17 am on May 14, 2011 (gmt 0)
1 site with 1000 pages. 1k pages are not too many to begin with, build it up, and once your domain matures and claims authority, you will rank for all pages. In 5 domain cases, you will have to manage 5 sites, possibly 5 different hosting, dedicated links to each domain and probably. With 1 site, you will have 1 hosting, focal point will be one site, mental burden will be less, actual burden and responsibility will be less. In 1K page site, users will be to browse other related content, which means more page views.