Useful Keyboard Shortcuts

Format any selected object, press ctrl+1
Insert current date, press ctrl+;
Insert current time, press ctrl+shift+;
Repeat last action, press F4
Edit a cell comment, press shift + F2
Autosum selected cells, press alt + =
Recalculate formulas, press F9
Select data in current region, press ctrl+shift+8
See formulas in the worksheet, press ctrl+shift+` (ctrl+~)
While editing formulas to change the reference type from absolute to relative vice versa, press F4
Format a number as currency, press ctrl+shift+4 (ctrl+$)
Apply outline border around selected cells, press ctrl+shift+7
Open the macros dialog box, press alt+F8
Copy value from above cell, press ctrl+’
Format current cell with comma formats, press ctrl+shift+1
Go to the next worksheet, press ctrl+shift+pg down
Go to the previous worksheet, press ctrl+shift+pg up

View the suggest drop-down in a cell, press alt + down arrow
Enter multiple lines in a cell, press alt+enter
Insert a new sheet, press shift + F11
Edit active cell, press F2 (places cursor in the end)
Hide current row, press ctrl+9
Hide current column, press ctrl+0
Unhide rows in selected range, press ctrl+shift+9
Unhide columns in selected range, press ctrl+shift+0