The other side of the coin is, of course, the Iraq War. We needn't debate that, because we'll surely violently agree, but let's not pretend the Blair/Brown partnership didn't lead to many positive things for the UK. It did.
Like the other commenter, I think that his interventions in the NHS were potentially short-sighted and ultimately more damaging than they were worth. It feels to me that rigorous performance metrics and PFIs contributed - along with subsequent under-funding by Tory governments - to running it into the ground.
I will concede however that the minimum wage and Good Friday Agreement are big wins!