Only if you plan on buying a new computer with a major update released after 10.4.2 -- then there is a good chance that computer will have a copy of the latest OS X version on it's System Restore DVD.
Of course these machines will also fail to work with the OS X Update released prior to its release. Thus a machine requiring Mac OS X v 10.4.3 won't work with the 10.4 retail box -- and you'll need the System Restore DVD or the next OS release 10.5.
Apple usually ships one version of the retail box, unless there is a severe problem requiring a recall of the boxes.
System Restore DVDs get updated, the retail box -- not.