How do you append new rows to the end of a workbook?

If I find the last row using ActiveCell.SpecialCells(xlLastCell).Row and
append my stuff, I often find blank rows above the newly appended ones
because somebody had entered data and then cleared it, which moves the
LastCell downwards.

I am trying to delete the blank rows by looping thru all rows to detect
blank ones, but the IsBlank function won't work in VBA. Are there
workarounds?