> What are the conferences that you are
> really excited about this year, and
> what tracks do you think will be the
> most beneficial to a sysadmin?

That's a hard question to answer.  The term sysadmin is really pretty broad in todays terminology especially if you work in a large enterprise.  If you work in a small it shop then you may want to look at whatever products you use the most and then focus going to an event where they discuss those products the most.  I also recommend joining user groups for products that you use or look at using.  Many of the user group events are free and local to your are, so it gives you a great opportunity to meet other people in the field and learn more about a product.  Many of the conferences are large in size, but the user group events are usually small.  Both have there pro's and con's, the larger ones allows you to network with a larger group of people, while the smaller ones give you a smaller student to teacher ratio giving you the best opportunity to ask questions and find answers.  Here's a list of several conferences that I'm aware of many of them either I or some of my co-workers have attended. 

 - [Microsoft Tech Ed][1] which focuses on Microsoft Products.
 - [Symantec Vision][2] for all Symantec products.
 - [VMware VMworld][3] for VMware products.
 - [Citrix Synergy][4] for Citrix Products.
 - [Briforum][5] for Desktop Virtualization, Server Virtualization, and Server Based Computing (RDS, Terminal Server, etc.)
 - [Storage Network World][6] for storage admins.
 - [Cisco Live][7] for Cisco networking admins
 - [O'Rielly][8] has several conferences throughout the year why topics from Rails, MySQL, Open Source, Web 2.0.
 - [Gov 2.0 Summit][9] for IT in the government.
 - [Gartner Symposium/ITxpo][10] for IT forecasting and analysis
 - [Impact][11] for IBM WebSphere admins
 - [Lotusphere][12] for various IBM Lotus products such as Domino, Sametime, Notes, etc.


  [1]: http://www.microsoft.com/events/techednorthamerica/
  [2]: http://www.symantec.com/vision/index.jsp
  [3]: http://www.vmworld.com/index.jspa
  [4]: http://www.citrixsynergy.com/
  [5]: http://briforum.com/
  [6]: http://www.snwusa.com
  [7]: http://www.ciscolive.com/
  [8]: http://conferences.oreillynet.com/
  [9]: http://www.gov2summit.com/
  [10]: http://www.gartner.com/technology/symposium/orlando/about.jsp
  [11]: http://www-01.ibm.com/software/websphere/events/impact/index.html
  [12]: http://www-01.ibm.com/software/lotus/events/lotusphere2011/