The game Dance Dance Revolution has become very popular in North America, and so have arcade-style metal dance platforms!  I don't claim to be an expert, but I do have some tips for people looking to buy DDR Platforms for the home:

More expensive DOES NOT MEAN BETTER, but generally you'll get more out of a $300 BlueShark or Cobalt Flux than you will out of a $100 tx-1000 clone.

If money's not an issue, I highly recommend the BlueShark, Cobalt Flux, DT500 series (my own designs, should be available by request within the next eight months), and Homebrew pads, homemade platforms which have become increasingly popular of late. (it's actually a simple process that can cost anywhere from $50 to $450 per controller, depending on what you want out of it)

If you're looking for something on the lower end of the price scale, look for Nexens, DT600 series (also my own), or, once again, homebrew.

If you want quality softpads, the Ignition 2.0 and the BNS Sparkle and Fusion pads are the best you can get, or you can modify a standard softpad. (see ddrfreak.com's Controllers forum for details)

Finally, those who wish to play on the computer should get StepMania (www.stepmania.com) and the EMS USB2 convertor. (Play-Asia.com is the most reliable seller of these)

The DT500 and DT600 series pads will hopefully be available in 2007; we're a small Oregon company dedicated to making quality Rhythm Gaming controllers of all kinds for the lowest price possible.  In addition to dance platforms for DDR, we also have platforms for Pump It Up, ParaParaParadise controller mod-kits, Guitar Heroes controller mod-kits, and we're even working on designing a whole new disco rave dance game of our own!