The next generation processor scheduled to come after Barcelona and AgenaFX will have 6MB of L3 cache. Barcelona and Agena FX, also known as the K10, will have only 2 MB. We already talked about Shanghai here.
We are still not sure about the quantity of L2 cache but it will be somewhere between 512 KB and 1 MB per core. This 45 nanometre chip will come in 2008 so we still have the time to worry about it.
It should be just on time to fight Intel with its 45 nanometre quad duct taped core.