You might want to think about what kind of network you think is 'crappy'. AFAIK, virgin actually runs on the t-mobile network, which from 1997 until 2005 when I left the UK, couldn't fairly be described as 'crappy'. What you might want to be concerned about is someone like Vodaphone or Orange getting the contract, because both of those companies like to customise the firmware to make it as difficult as possible to use the phone as you wish, so you're tied into their downloads and features. I can't see Apple allowing that to happen though.
I suspect that Apple's UK partner will be either O2 or Vodaphone.
BTW, on to your other question, UK phone companies are far more generous than they are here in the US in regards to the hardware you get with a contract - so it's entirely possible for the 1st time ever that UK buyers may get a better deal on the iPhone than US consumers,