I share my backup exclusion list as a typical Ubuntu and Gnome user in case some one might find it useful.
Save some of the exclusion lists, check backup size before manual backup.
$ du -sh -X exclude.lst ~
Note the first two folders normally residents in ~/.mozilla/firefox/*/
OfflineCache Cache .beagle .cache cache .Trash .local/share/Trash .thumbnails .~lock.* *~ .*.swp
Note the first two folders normally residents in ~/.mozilla-thunderbird/*/
ImapMail global-messages-db.sqlite Downloads incoming music Music Movies Videos *.avi *.AVI *.rm *.RM *.rmvb *.RMVB *.mkv *.MKV *.ape *.APE *.dc++ My Music MyMusic .wine .cxoffice cxoffice .vmware
Dropbox public_html Photos
Since the exclusion list lines are the only lines in this file that don't contain HTML, to grab the whole list:
$ wget -qO - http://www.zhangweiwu.name/100429.html | grep -v -e '[<"]' -e '^$'