Biggest mistake, TARP. Second, allowing himself to be treated as a doormat/punching-bag by the libs & media, without ever fighting back. Otherwise, a decent prez, although not conservative enough on the small government front. Regardless, infinitely better than the current POS we have.
No doubt W was better than Obama, but not infinitely better. But there were major problems with W's presidency. For one thing, spending was out of control. W did understand that the enemy is radical Islam, but he didn't have the courage to talk about that directly. Instead he talked about "terrorism". And once he started the war, W mismanaged it by trying to wage a kinder and gentler war.
Perhaps Republicans will get back on track now that the Tea Party has gained some traction.