Mac OS X Key Commands (in a text editor)

Command-Up (Arrow)/Command-Down moves the inser­tion point to the begin­ning or end of a doc­u­ment.
Command-Left/Command-Right moves the inser­tion point to the begin­ning or end of a line of text.

Option-Up/Option-Down moves the inser­tion point to the begin­ning or end of a string of text. (It will jump sev­eral lines to the next “hard return”)
Option-Left/Option-Right moves the inser­tion point to the begin­ning of the current/previous word or to the end of the current/following word. (Read­ing left-to-right)

Control-Up/Control-Down scrolls the doc­u­ment to the top or bot­tom with­out mov­ing the inser­tion point.
Control-Left/Control-Right moves the inser­tion point to the begin­ning or end of a line or text. (same as using Command)

Apple’s sup­port doc­u­ment (http://support.apple.com/kb/HT1343) does not seem to list these oper­a­tions as per­formed in a text editor/document.

Speak­ing of text edi­tors, I use and am not get­ting paid to men­tion Coda. The app has a slick inter­face, nice design, imple­ments the above key com­mands, and is backed by a help­ful, respon­sive staff.