The best replacement for google docs is microsoft office.

The best alternatives to google docs are rated as following:
★★★★★  microsoft office
★★★★  dropbox
★★★  zoho
★★★  evernote
★★★  google drive
★★★  opengoo
★★★  thinkfree
★★  office
★★  sharepoint
★★  microsoft word
★★  word
★★  office 365
★  open office
★  skydrive
★  excel
★  office live
★  iwork
★  openoffice
★  microsoft office 365
★  box.net
★  libreoffice
  basecamp
  windows live
  office online
  survey monkey
  office web apps
  wiki
  onenote
  onedrive
  pages
  ms office 365
  microsoft cloud
  quickoffice
  apple pages

Your alternative for google docs is not listed? Suggest!
Speaking about google docs, one probably shouldn't forget about dropbox.

Other search terms related to google docs and their ratings are:
★★★★★ dropbox
★★ basecamp
★★ ocr
You have in mind a companion for google docs and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of google docs in all years. Click on graph for more.
google docs
microsoft office
dropbox