[Xperia Arc Q&A, Help & Troubleshooting] tainguyen2704:
Safe to remove for all stock rom Arc:

AccessoryKeyDispatcher.apk --- event listener (unsure of trigger, hardware and handsfree keys work without it.)

Calculator.apk --- default calculator

CdfInfoAccessor.apk --- Software Component Descriptions

chinesetextinput.apk --- chinese keyboard

com.sonyericsson.androidapp.foursquare_ext_ts3.apk --- Timescape Foursquare Extension

com.sonyericsson.androidapp.timescapefeedsplugin.a pk --- Timescape Feeds

com.whatsapp.apk --- Whatsapp

*CoreNotificationPublisher.apk --- Lock Screen Notifications

CrashSMS.apk --- Diagnostics Tool (debug helper)

datatrafficswitch.apk --- mobile data on/off widget

DigitalClockWidget.apk --- clock widget

DownloadProviderUi.apk --- default browser downloads folder

EventStream.apk --- Timescape

EventStreamPluginCallLog.apk --- Timescape Call Log Extension

EventStreamPluginFacebook.apk --- Timescape Facebook Extension

EventStreamPluginTelephony.apk --- Timescape Telephony extension

EventStreamPluginTwitter.apk --- Timescape Twitter extension

facebook.apk --- Facebook

*FBCalendarSync.apk --- Sony Ericsson Facebook Integration Calendar Sync

*FBMediaDiscovery.apk --- Sony Ericsson Facebook Integration Media Discovery

*FBMusicLike.apk --- Sony Ericsson Facebook Integration Music Like

*FBNotificationPublisher.apk --- Sony Ericsson Facebook Integration Facebook Notifications

*FBSetupwizard.apk --- Sony Ericsson Facebook Integration Setup Wizard (not needed to setup or for FB Integration to work)

GenieWidget.apk --- News and Weather

Gmail.apk --- Gmail app

GoogleFeedback.apk --- Market Feedback Agent (forceclose reporting for apps installed from Market)

GooglePartnerSetup.apk --- Google Partner Setup (no longer needed after setting up Gmail)

GoogleQuickSearchBox.apk --- google quick search box

HTMLViewer.apk --- HTML viewer (view HTML files directly from file manager)

IddAgent.apk --- Anonymous Usage Stats

JapaneseIME.apk --- japanese keyboard

LearningClient.apk --- learns user typed words for default keyboard

letsgolf_A_353.apk --- Let's Golf game

LiveWallpapers.apk --- Live wallpapers pack

LivewareManager.apk --- Liveware Manager

MagicSmokeWallpapers.apk --- Live wallpaper

MediaWidget.apk --- Media shortcuts widget

MediaUploader.apk --- My Uploads for Youtube uploading (not needed if just watch Youtube)

MusicWidget.apk --- default Music player widget

*NotificationProvider.apk --- Lock Screeen Notifications Storage

officesuite.apk --- Office Suite

OmaDatasyncService.apk --- Sony Ericsson Sync

PhotoWidget.apk --- Picture Frame widget

*playnowclientarvato.apk --- Playnow Store (replaces the 2 APKs in the list directly below)

playnowappinstaller.apk --- Playnow updater

playnowclient.apk --- Playnow

POBoxSknPink.apk --- japanese keyboard skin

POBoxSknWood.apk --- japanese keyboard skin

Protips.apk --- Pro Tips widget

qcsemcservice.apk --- RIL extension for default browser

Radio.apk --- FM radio

retaildemo.apk --- retail demo

SecureClockJava.apk --- web clock service (some DRM or Secure services may use this, restore if you need it.)

SemcCrashMonitor.apk --- debugger

SemcDlna.apk --- media server

*SEMCFacebookService.apk --- Sony Ericsson Facebook Integration Service

SEMCSetupWizard.apk --- setup wizard

SemcVideoEdit.apk --- video editor

SoundRecorder.apk --- sound recorder

StatusSwitch.apk --- Status switch widget

Stk.apk --- Sim Tool Kit

Street.apk --- Google Street view

SyncWizard.apk --- Sony Ericsson Sync Account

timescapelegacywrapper.apk --- Timescape plugin

TimescapeSpline.apk --- Timescape widget spline

TimescapeWidget.apk --- Timescape widget

touchnote.apk --- Touch notes postcard

trackid.apk --- TrackID

*UnsupportedHeadsetNotification.apk --- Possibly a notification when pairing with unsupported bluetooth headsets

usersupport.apk --- Support

VisualizationWallpapers.apk --- Live wallpaper

WallpaperPicker.apk --- Sony Ericsson Wallpapers

widgetdigitalclock.apk --- clock widget

widgetonoff.apk --- widget on/off toggles

YouTube.apk --- YouTube