The best replacement for windows 2008 is r2.

The best alternatives to windows 2008 are rated as following:
★★★★★  r2
★★  windows 2003
★★  2008r2
★★  windows 2008 r2
★★  2008 r2
★  linux for server
★  windows 2012

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

Other search terms related to windows 2008 and their ratings are:
★★★★★ hyper v
iis7
You have in mind a companion for windows 2008 and it is not yet here? Propose!



Google Trends

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windows 2008
r2
windows 2003