There are two Lion features with similar affects:
1. Reopen windows
2. Auto Save
If you don't save the contents of some applications, it can reopen.
You should do a few things:
1. Save any items that might need saving, especially documents and projects of that nature
2. Remove undesired login items from Sys Prefs > Users/Groups > Login Items (not Login Options)
3. Remove undesired applications from /library/startupitems/
4. Disable reopen windows in Sys Prefs > General
5. Disable reopen windows when logging out, restarting, or shutting down
If the above do not fix it, then test in Safe Boot as well as a new user to determine what might be going on.