What were the smartest strategic technology acquisitions?

To help others answer this better...

There's a great list here -- http://www.ranker.com/list/the-smartest-tech-startup-acquisitions-ever/ready-to-startup

And a google doc here (itemized below) -- https://docs.google.com/spreadsheet/pub?key=0Ag0BxADNLZqgdHdzYVR3a3BoM09jLUxNMC1lMDk2amc&single=true&gid=0&output=html

• Geocities - Yahoo
• Broadcast.com - Yahoo
• Webshots - Excite@Home
• Mapquest - AOL
• eGroups - Yahoo
• Paypale - Bay
• Blog­ger - Google
• Picasa - Google
• Webshots - CNET
• Live­Jour­nal - Six Apart
• Flickr - Yahoo
• Dodge­ball - Google
• MySpace - News Corp
• Skype - eBay
• IGN - News Corporation
• Upcoming.org - Yahoo
• del.icio.us - Yahoo
• Grouper - Sony
• YouTube - Google
• Last.fm - CBS
• StumbleUpon - eBay
• FeedBurner - Google
• Jaiku - Google
• Bebo - AOL
• CNET - CBS
• Zappos - Amazon
• Mint.com - Intuit
• Aardvark - Google
• Huffington Post - AOL
• Gowalla - Facebook
• OMGPop - Zynga
• Instagram - Facebook
• ...

And here -- http://techcrunch.com/2009/12/18/top-tech-acquisitions-2009/
...Which is part of this -- http://www.crunchbase.com/acquisitions?page=1