I did some cleaning days ago. these are the softwares that are HUGE and sometime useless.
1. iWorks, this stuff will expire in 30 days, after which you will not be able to save the work you made with it, if you are not going to use it, then delete it, size: 1.9GB
2. GarageBand, well, unless you use it, then you need to get rid of it, size: 2GB, note, the application file is around 100MB, but real library file is HUGE, be sure to use spotlight to search for any file related to it and delete them
3. iDVD, as described, this stuff is about 1GB in size, mostly themes, delete it if you don't use it
4. MS Office trial version, about 350MB. even if you buy a retail version, you still need to delete this one before the installation of new one, so just do it now.