Nicely tabulate a list of strings for printing

I have a list of strings of variable lengths, and I want to pretty-print them so they are lining up in columns. I have the following code, which works as I want it to currently, but I feel it is a bit ugly. How can I simplify it/make it more pythonic (without changing the output behaviour)?

For starters I think I could probably use the alignment '<' option of the str.format stuff if I could just figure out the syntax properly...

def tabulate(words, termwidth=79, pad=3):
  width = len(max(words, key=len))
  ncols = max(1, termwidth // (width + pad))
  nrows = len(words) // ncols + (1 if len(words) % ncols else 0)
  #import itertools
  #table = list(itertools.izip_longest(*[iter(words)]*ncols, fillvalue=''))  # row-major
  table = [words[i::nrows] for i in xrange(nrows)]                          # column-major
  return '\n'.join(''.join((' '*pad + x.ljust(width) for x in r)) for r in table)

A slightly more readable version:

def tabulate(words, termwidth=79, pad=3):
    width = len(max(words, key=len)) + pad
    ncols = max(1, termwidth // width)
    nrows = (len(words) - 1) // ncols + 1
    table = []
    for i in xrange(nrows):
        row = words[i::nrows]
        format_str = ('%%-%ds' % width) * len(row)
        table.append(format_str % tuple(row))
    return '\n'.join(table)

Most notably, I've defined width to include padding and using string formatting to generate a format string to format each row ;).

StackExchange Code Review Q#21159, answer score: 3