If we are talking £7m for Yak, then there is no chance at all of us letting him go. Let's see what our other options are- Saha is, what, 33? He's a fine player but his legs aren't going to last anywhere near a full season. As for Vaughan, I can't believe people are actually expecting him to make any sort of significant contribution, and he certainly isn't anywhere near to leading the attack for us. Beckford will hopefully become a regular scorer for us, but he is stepping up two whole divisions and it is a massive jump, and he has a lot to learn at this level. We certainly can't rely on him to provide us with a steady supply of goals until we assess how well he adapts to life in the PL, and that might not be until the 2nd half of the season. Silva hasn't even featured pre-season, so he's obviously not ready for PL action.
Now considering that, what if - touch wood - Saha went and got injured? That would leave us with Beckford & Vaughan. Can you see Chelsea or Mancs quaking in their boots at the prospect of facing us with this strike pairing?