I use these all the time… especially holding Option or Command while using the arrows to move the cursor around.
To select text you hold down the SHIFT key and then use the arrow keys or HOME, END, PAGEUP, and PAGEDOWN. The left/right arrow keys (plus SHIFT) will increase the selection one character in that direction, if you hold down the OPTION (⌥) key the left/right arrows will select an entire word in that direction, and if you hold down the ⌘ key the left/right arrows will select to the beginning or end of the line. The up/down arrow keys (plus SHIFT) will select a full line up or down; with the OPTION key held down the up/down arrows will select a paragraph. The HOME key (plus SHIFT) will select all the text to the beginning of the document and the END key (plus SHIFT) will select all the text to the end of the document. Finally, the PAGEUP and PAGEDOWN keys (plus SHIFT) will select a full “page” up or down.
Mac 101: Keyboard text selection – The Unofficial Apple Weblog (TUAW).
You only need to hold Shift if you want to select text. Without holding shift, the aforementioned key commands will just move the cursor around. You probably don’t realize how much time you waste trying to point with that Trackpad on your MacBook.