Shouldn't the pH at the equivalence point always be 7?
Two kinds of reactions have to be considered:


Neutralisation of the weak acid with the strong base
Secondary reactions from the products


The neutralisation is fairly straightforward:
$$\ce{HA + NaOH -&gt; NaA + H2O} $$

However, and here comes number two from the list: It doesn't just stop there because we still have unreacted acid in the solution and lots of water. So what will happen? The conjugated base of the acid can also react (as a base):
$$\ce{A- + H2O &lt;=&gt; OH- + HA}\; ,$$

thus raising the pH of the solution. This depends on the equilibrium constant $\mathrm{K_b}$ of the conjugated base.

So although you have reacted exactly equal amounts of a (strong) base with the (weak) acid, you also have to consider the (weak) conjugate base of the acid, which also swims around in your titration soup.