If you're having trouble with Delay activities not returning in SharePoint workflows, head over to this entry from the SharePoint team blog for status and information on how to help us identify the issue:) Thanks much!
Update: Thank you everyone for your patience and for sending us your workflows and information! I wanted to let you know that the fix for the “delay” issues is included in the Infrastructure Updates that were released on 7/15, so please download those to get this. We did notice that there seemed to be some other causes that can be fixed from the developer side, so we put together a KB to summarize our findings and tips for working around them at http://support.microsoft.com/kb/953630/. We hope this will be the last of the delay issues, but if you continue to run into issues, please let us know.