I think it all depends on personal needs and preferences. For example I have my signature PC: Intel G860 + GTX 550Ti. Which is a mid-low end gaming PC. I do not play heavy games like BF3 or SC2 online and neither do I play games like BF3 at all. So do I need a better PC? Not really. This PC can already play all games at atleast normal settings.
However, my personal preference is to purchase Haswell when it comes out, just because I like new and best technology. I don't really like compromises in PCs. It's either SB or HW for me. I can live with my current PC until HW and Nvidia 7 or Radeon 8 series comes out. Then I'll probably be happy with that build for a year.
But then I'm young and inexperienced so I could be wrong