"I'm wondering if its considered to be best practise that a switch should act as a root bridge where the first routable SVI instance is located."
I wouldn't say it's a best practice, but it's often a common practice. It really depends on what your L2 and L3 topologies are. If the are congruent, then having have the root of your STP on the same device as the corresponding L3 gateway, often makes sense.
BTW, often common, if using a FHRP, a backup gateway is also often the secondary root bridge.