Which startup applications can I safely turn off? [duplicate]

Solution 1:

Bluetooth manager: bluetooth won't work until you re-enable it and re-login
disk notifications: don't disable it, it will warn you if your disk is going to die soon!
login sound: safe to disable
GSettings data conversion: I would leave this turned on, as it might cause problems in the future otherwise
power manager: you better keep this running
remote desktop: might be okay if you don't use it
Ubuntu One: again, if you don't use it...
User folder update: might be useful to keep it in case of changes in the future
visual assistance: if you are 100% sure nobody will ever need accessibility tools on this system...

I'd leave GSettings Data Conversion, Disk Notifications and Power Manager alone.

Please imagine a sidenote about "how this most likely won't effect the overall performance" here. Thank you.