Before you start reorg'ing or rebuilding your indexes, ask yourself:

Are we actually having any performance issues with the database? What have your users said?

What is the profile of the data in the table? How many inserts / deletes / updates?

When were the statistics last updated on the tables?

If rebuilding, when can you do this? Controlled outage? Online or Offline rebuild? How will this affect the disk space on the server?

Have a read of these two articles before you proceed as it requires a bit more thought other than which option you should choose.

http://blogs.msdn.com/b/psssql/archive/2012/09/05/how-it-works-online-index-rebuild-can-cause-increased-fragmentation.aspx

http://www.mssqltips.com/sqlservertip/2361/rebuilding-sql-server-indexes-using-the-online-option/

cheers,

Shaun