Can the DS1052E be used for reliable NTSC measurement?
Wikipedia provides the following information (see NTSC, PAL and SECAM Overview PDF for an in-depth look):


  An NTSC television channel as transmitted occupies a total bandwidth
  of 6 MHz.


The Rigol DS1052E has a bandwidth of 50Mhz, which is sufficient.  It also has special video triggering modes, which will be useful.  There is a tutorial from Rigol on Youtube about using this triggering mode to capture a video signal (this uses a much more capable scope).  Alternatively there is a third party video about the triggering modes on the DS1052E.

VGA is faster (>25Mhz) so will will start to test the limits of the scope, especially if you want to capture longer waveforms.  There are also multiple signal connectors and the DS1052E only has two channels.