The real trick is, determining what your mom wants or needs, content-wise. She won't be able to access the entire internet w/o connecting a real PC or Mac to the display. Neither the HDTV or Blu ray player have hard drives, FWIW. They can however use built in applications to stream/access specific content from the internet, such as youtube, pandora or netflix, some of which involves paid subscriptions. She wouldn't be limited to an HDTV with 'widgets' as some Blu ray players have them too.
My mom is thinking about getting a 46 inch Samsung (looking at the LN46C650 or UN46D6000) and either a dvr or a blue ray player with a hard disk. She also wants surround sound. Is it necessary to buy a TV with internet or can she just use the blue ray player. Do any of these come with a hard disk? If the tv is wi-fi ready, what does this mean?