It truly depends on the fabric. I'm a big fan of the Eagle Creek cubes/envelopes and find it easier to pack and keep track of what's where (have different colors for different contents). That said, some things still get wrinkled, so I pack a little spray bottle of Downey Wrinkle Release, which helps. I've used it on my husband's suits with good result.

http://www.drugstore.com/downy-wrink...fromsrch=Downy