Can be deleted optionally
com.apple.accessoryd.plist - Removing this will make accessories such as docks and other cables not be able to do anything except charge.
com.apple.AddressBook.plist - If you don't care about your contacts loading slower, delete this.
com.apple.AdminLite.plist - When and app is not responding, this force closes it. You'll have to wait for unresponsive apps if you delete this.
com.apple.AOSNotification.plist - Delete this if you don't use iCloud and other similar services.
com.apple.apsd.plist - This daemon deals with Push notifications and iMessage. If you don't use those, you can delete them.
com.apple.assitivetouchd.plist - If you don't use Assistive Touch, delete this.
com.apple.daily.plist - Deals with automatic App Store updates. Delete this if you don't mind doing it manually.
com.apple.dataaccess.dataaccessd.plist - This daemon deals with syncing with Exchange and Google Sync. If you don't use those services, feel free to delete this.
com.apple.gamed.plist - If you don't user GameCenter, delete this.
com.apple.itunescloudd.plist - Delete if you don't use iTunes cloud or Home Sharing.
com.apple.iapd.plist - Deals with companion apps for accessories. Delete if you don't you don't have any.
com.apple.MobileInternetSharing.plist - If you don't want to use internet tethering, or if you don't have an iPhone or a 3G iPad, delete this.
com.apple.mobile.obliteration.plist - Feel free to delete this if you don't use remote wipe.
com.apple.mobile.profile_janitor.plist - If you don't use ad-hoc app distribution, delete this.
com.apple.printd.plist - Delete this if you don't use AirPrint
com.apple.racoon.plist - Delete this if you don't use Virtual Private Networks.
com.apple.scrod.plist - You can delete this if you don't use voice control.
com.apple.searchd.plist - Deals with Spotlight search. If you don't find yourself using it, delete it.
com.apple.search.appindexer.plist - Deals with indexing apps to appear in Spotlight search. You can delete this if you don't use Spotlight.
com.apple.storage_mounter.plist - The iPad Camera Connection Kit depends on this daemon. Delete if you don't use it, or if you don't have an iPad.
com.apple.twiterd.plist - If you don't use in-app Twitter, delete this.
com.apple.vibrationmanagerd.plist - If you don't use custom vibrations, or if you have an iPod touch, delete this.
com.apple.voiced.plist - Deals with voice control. Delete if you don't use.
com.apple.VoiceOverTouch.plist - Same as above. Another voice control daemon.
com.apple.vsassetd.plist - Voice control; same as above.
com.apple.wapic.plist - Deals with errors with Wifi networks with Chinese characters in the name.
com.apple.AddressBook.plist - If you don't care about your contacts loading slower, delete this.
com.apple.AdminLite.plist - When and app is not responding, this force closes it. You'll have to wait for unresponsive apps if you delete this.
com.apple.AOSNotification.plist - Delete this if you don't use iCloud and other similar services.
com.apple.apsd.plist - This daemon deals with Push notifications and iMessage. If you don't use those, you can delete them.
com.apple.assitivetouchd.plist - If you don't use Assistive Touch, delete this.
com.apple.daily.plist - Deals with automatic App Store updates. Delete this if you don't mind doing it manually.
com.apple.dataaccess.dataaccessd.plist - This daemon deals with syncing with Exchange and Google Sync. If you don't use those services, feel free to delete this.
com.apple.gamed.plist - If you don't user GameCenter, delete this.
com.apple.itunescloudd.plist - Delete if you don't use iTunes cloud or Home Sharing.
com.apple.iapd.plist - Deals with companion apps for accessories. Delete if you don't you don't have any.
com.apple.MobileInternetSharing.plist - If you don't want to use internet tethering, or if you don't have an iPhone or a 3G iPad, delete this.
com.apple.mobile.obliteration.plist - Feel free to delete this if you don't use remote wipe.
com.apple.mobile.profile_janitor.plist - If you don't use ad-hoc app distribution, delete this.
com.apple.printd.plist - Delete this if you don't use AirPrint
com.apple.racoon.plist - Delete this if you don't use Virtual Private Networks.
com.apple.scrod.plist - You can delete this if you don't use voice control.
com.apple.searchd.plist - Deals with Spotlight search. If you don't find yourself using it, delete it.
com.apple.search.appindexer.plist - Deals with indexing apps to appear in Spotlight search. You can delete this if you don't use Spotlight.
com.apple.storage_mounter.plist - The iPad Camera Connection Kit depends on this daemon. Delete if you don't use it, or if you don't have an iPad.
com.apple.twiterd.plist - If you don't use in-app Twitter, delete this.
com.apple.vibrationmanagerd.plist - If you don't use custom vibrations, or if you have an iPod touch, delete this.
com.apple.voiced.plist - Deals with voice control. Delete if you don't use.
com.apple.VoiceOverTouch.plist - Same as above. Another voice control daemon.
com.apple.vsassetd.plist - Voice control; same as above.
com.apple.wapic.plist - Deals with errors with Wifi networks with Chinese characters in the name.