or use advanced task killer, which lets you put it on ignore.
You can also improve speed, as well as battery life, by deleting a lot of the "sony ericsson" crap found under "backup" when opening titanium. Additionally, delete SE's "home" if you don't use it and any language packs under "system/user/keyboard-config" and "system/usr/zi"
I've also erased bluetooth, GPS, maps and text to speech (since i don't use them) without any problem.
Other tips for saving space -
Delete unecessary ringtones, alarms etc... under system/media/audio
Delete unecessary wallpaper from system/etc/customization/content/com/sonyericsson/homescreen/wallpaper
Delete boot animation (sorry, can't remember where this was)
Of course this isn't for averyone but personally I like a slimmed down, respnsive phone