- Home - To the top of current column
- End - To the bottom of the current column (the last cell with data)
- Ctrl-Home - To cell A1
- Ctrl-End - To the last non-empty cell in the highest row that has data in it Update: to the last cell as described by openBrain, below.
- Ctrl-Arrow - To the last cell in the data block with data in it (e.g. find the first empty cell, stop before it)
- Tab/Enter - Count the number of tabs, return to the starting column on "Enter"
Update: I also implemented block selection from the keyboard using the shift modifier with the arrow keys.