If you're looking for more bang for the buck, go -1 up front (16T). I think FGB is correct that even going two up in the back is not as effective as 1 down on the front sprocket.
I've done the 16T thing, and am contemplating going up 2 in the back. If you do either, your speedo will be off, and you'll need to correct it. Yellowbox and SpeedoHealer are the popular choices. I'd highly recommend going with the version 2 SpeedoHealer. It's a great product, and I've gotten fantastic support from the company.
Ping me if you have any questions about the SH.
Good luck.