High def is worth it.
If you do get one, do lots of research.
Research:
Different types of tv's( plasma, dlp, lcd...)
Different types of high def (720p,1080I, and 1080p)
there are some tvs that are listed as high def but they dont display the whole picture. The minimum resolution for high def is 1,280x720. I have a friend who just got a dell plasma. it says high def but only displays 1080x720(or something like that). the picture is cut off! you cant see the score icon on the top right of the screen for football games. it really sucks. get 1080p if you can, its highest definition available.
also, make sure what HDTV source you are going to use. if you are going to use comcast, you have to upgrade the cable box. make sure your tv is cable ready.
if you are getting hd over the air, make sure your tv has a hdtuner built in
there are a lot of things to consider, do the research.
the tv is worth it!
here is a nice site to help.
http://www.cnet.com/4520-7874_1-5108580-3.html
Most importantly: go to the store and look at the tv's side by side. go to several differnt stores. take your time and pick which you like most, then go online and research the pros and cons of the model.
good luck