Additional queries that aren't covered by the options bitfield:

Threaded Mode
On: UPDATE user SET threadedmode=1
Off: UPDATE user SET threadedmode=0

Popup on new PM
On: UPDATE user SET pmpopup=1
Off: UPDATE user SET pmpopup=0

Default daysprune setting
UPDATE user SET daysprune=X
where X is the number of days

Language
UPDATE user SET languageid=X
where X is the ID of the language (you can get this from the admin CP)

Style
UPDATE user SET styleid=X
where X is the ID of the style (you can get this from the admin CP)

First day of the week
UPDATE user SET startofweek=X
where X is a number 1 through 7 indicating the first day of the week (with 1 being Sunday, 2 being Monday, etc)

Message Editor Interface
Do Not Show Editor Toolbar: UPDATE user SET showvbcode=0
Show Standard Editor Toolbar: UPDATE user SET showvbcode=1
Show Enhanced (WYSIWYG) Editor Toolbar: UPDATE user SET showvbcode=2

Thread subscription/email notification defaults
Do not subscribe: UPDATE user SET autosubscribe = -1
Subscribe without notification: UPDATE user SET autosubscribe = 0
Instant email: UPDATE user SET autosubscribe = 1
Daily email: UPDATE user SET autosubscribe = 2
Weekly email: UPDATE user SET autosubscribe = 3

Show Birthday
Hide Age & Date of Birth: UPDATE user SET showbirthday = 0
Display Age: UPDATE user SET showbirthday = 1
Display Age & Date of Birth: UPDATE user SET showbirthday = 2

Timezoneoffset
UPDATE user SET timezoneoffset = X
where X is the GMT value (0, 2, -5, )