People make too much of the price at which players are signed when determining who belongs on best and worst lists. At the end of the day, managers are given a budget and they spend it. The players who are brought in should be measured on what they bring to the team. I would agree that despite his high transfer price and wages, Toure has easily been one of the best buys in the league this season. Don't penalize him for being a good player to start with.
I actually think this over-emphasis on transfer fees is one of the reasons that Wenger has escaped more stringent scrutiny. Wenger has brought in a lot of shit players. People just don't complain about it as much because we did not spend 30 million pounds on them. But at the end of the day, a shit player is just as unlikely to win you a trophy whether you bought him for £500,000 or £50 million