The best replacement for windows server 2008 is windows 7.

The best alternatives to windows server 2008 are rated as following:
★★★★★  windows 7
★★★  2003
★★★  linux
★  linux fedora
★  windows server 2008 r2
★  fedora
★  windows server 2003
★  ubuntu
★  windows home server
★  2008 r2
★  small business server
  whs
  ubuntu server
  server 2003
  red hat linux
  home server
  windows vista
  windows server 2012

Your alternative for windows server 2008 is not listed? Suggest!
Speaking about windows server 2008, one probably shouldn't forget about hyper v.

Other search terms related to windows server 2008 and their ratings are:
★★★★★ hyper v
★ iis
★ mac clients
You have in mind a companion for windows server 2008 and it is not yet here? Propose!



Google Trends

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windows server 2008
windows 7
2003