My advice
Wait as long as you can, buy a Top-of-the-Line what ever comes out, with SCSI hard drives if you can afford it, and you'll be happy for some time. Even if you just use it for Video, speed is speed (unless you're talking Intels. DO NOT BUY PCs FOR AUDIO/VIDEO).
If you want to save some money, buy the new low-ends. Or older models at a huge discount if the memory and specs aren't better with the new ones. Or some ReFurb models. Use the money saved on a RAID array. Not sure what your budget is for this, though, or what it is you'll be using them for.
Don't forget, the current discount is on the displays. So either new displays are coming out, or current ones will be discounted (or both). Dual Displays with one LCD, one CRT are preferrable, and an NTSC (or Pal) display if you can.
Also, have you thought about using an Aurora Ignighter RT.
http://www.auroravideosys.com
Little cheaper (depends on your definition of cheap), but good products and good drivers (even OS X). Lot of options and better support.
Personally, I can wait. I guess I have to. But I would like an RTMac, if Matrox ever comes out with OS X driver. Otherwise, I can do without for now. Can't afford the Aurora I want just yet. We're definitely too small for a CineWave. I'm assuming you mean the HDTV one. Must be nice though.
Good luck.