no It doesn't require HDTV...it's only an recommendation that you get an HDTV for the best looking graphics ever seen possible but for me I use a 20' flat tube TV with AV inputs and S-video inputs for the PS2, Xbox, GameCube, and Xbox360 all connected to my TV so I would say S-Video is proably the best and cheap type of cables you could afford if you have a new TV that has S-Video input, then your good.
There are still a good selection of games you can get for Xbox360 such as Perfect Dark Zero, Call of Duty 2, Dead or Alive 4, Kameo : Elements of Power, Quake 4, Rumbel Roses XX, and later on Tomb Raider : Legend, The Godfather, and Gears of Wars are coming to Xbox360.
I've bought the core system because it was cheaper but already bought the HDD so I can play some of the orginal Xbox games on Xbox360 and have a charge and play kit for the wireless controller and an memory unit I can use for back up memory. I still dont have Xbox live, but it's still a pretty good damned gaming machine. Good thing you dont even need the media remote for DVDs cause you can still use the controller for DVD playback, as well.
PS3 won't be out until November, but I still plan to get the PS3 because of Metal Gear Solid 4 but dont know if I would like to get the PS3 at launch so perhas I would just wait and see...since I'm actually more of an Xbox fan than an Playstation fan.
So if you really want to get an Xbox360, then what your waiting for? go grab it!