I would probably subfloor the entire basement. If the subfloor is sound and you don't need waterproofing, then you don't need Ditra...you would use a backer of your choice. Thin set it down and screw it to the subfloor.
Installing plywood over the entire floor will also eliminate any floor height differences. 1/4" backer with a 5/16" thick tile should flush out really well.
Last edited by carolinacustomkb; 09-14-2011 at 04:27 PM.