if you wanna save some disk space under /system, here is the list for reference and tested (by assuming deodexed stock apps used)


WARNING: do it at your own risks!!!
You are suggested to do a backup before removing/renaming the files

AccountAndSyncSettings.apk
ApplicationsProvider.apk
AxT9IME.apk* <-- only if you have other input method
BadgeProvider.apk
Bluetooth.apk
BluetoothOPP.apk
BluetoothPBAP.apk
BluetoothServices.apk
Browser.apk <-- new installation requires this, DO NOT delete this if you have CSC.apk, or ONLY IF U R ADVANCED USER
CSC.apk <-- new installation requires this, but can be deleted ONLY IF U R ADVANCED USER
CalendarProvider.apk
CallSetting.apk
CameraFirmware.apk
CertInstaller.apk
Contacts.apk*
ContactsProvider.apk
DataCreate.apk
DefaultContainerService.apk
DialerTabActivity.apk
Divx.apk
DownloadProvider.apk
Email.apk <-- needed for some apps using the camera, will FC if removed
GoogleCalendarSyncAdapter.apk* <-- if you dont need calendar sync
GoogleContactsSyncAdapter.apk* <-- if you dont need contacts sync
GoogleQuickSearchBox.apk* <-- if you do not need search, but will FC if you typed a wrong url in the browser
GoogleServicesFramework.apk
HTMLViewer.apk*
InputEventApp.apk
LogsProvider.apk
MediaProvider.apk
MediaUploader.apk
Mms.apk*
PackageInstaller.apk
Personalization.apk
Phone.apk*
PhoneErrService.apk
Phone_Util.apk
SecDownloadProvider.apk
SecurityProvider.apk
Settings.apk
SettingsProvider.apk
Swype.apk* <-- only if you have other input method
TelephonyProvider.apk
TouchWiz30Launcher.apk* <-- only if you have another home screen
UserDictionaryProvider.apk* <-- may cause FC in some keyboards
Vending.apk
wssomacp.apk


*= can be removed if you want to