We just finished our basement not too long ago and screwed directly to the joists. It's a 52 year old house with 2x8 joists and it turned out great. In new houses everything is screwed directly to the joists but alot of joists used in the better housing now are TGI joists. Drywall is screwed directly to all the other joists, no different in the basement. WHen I say 'better housing' I mean custom houses.