There can be no question but that by Day the author meant just what we mean--the time required for one revolution of the earth on its axis. Had he meant an aeon he would certianly, in view of his fondness for great numbers, have stated the number of milleniums each period embraced. While this might have made his account of creation less irreconcilable with modern science, it would have involved a lessening of God's greatness, one sign of which was his power to do so much in one day.
In a similar vein, have a look at this piece on the Anglican site.
When we decide that we can set aside the truth value of the whole content of Genesis 1, we end up in the odd state that we say that we can infer truth from non-truth. The detail is too much to say it is merely figurative, and Simpson, quoted above, would agree: the author meant it! How can we infer what God did from what we say he did not do? If we set aside the direct meaning of Genesis 1 (and it is clearly not poetry, despite the protestations of some non-Hebrew readers) we have to give a reason as to why the detail of the revelation can be disregarded, when the whole Bible treats it as an account of actual events.
What it does is to say that something that doesn't give information about this world (the world it would speak of) gives instead information about some other world which doesn't exist in terms of Genesis 1 (that is an imaginary world, not the real world, as it holds that Genesis 1 doesn't touch the real world of what actually happened).