Dealing with NoData in ArcGIS Spatial Analyst?

I would have used the raster calculator with the following expression:

Con(IsNull([raster]), 0, [raster])

It assumes that your raster is called 'raster'.

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The 10.x Raster Calculator tool syntax is slightly different. In this example, "raster" is a layer in the map:

Con(IsNull("raster"), 0, "raster")

You can set NoData values to any value using the conditional operator Set Null ( ArcGIS 9.3, ArcGIS 10). I'm not aware of a way of preventing the NoData from appearing in the first place, though.

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I realized I should have written/linked to the Con operator as @AndOne mentioned.

From the documentation, if you use python:

import arcpy
from arcpy import env
from arcpy.sa import *
env.workspace = "C:/sapyexamples/data"
outCon = Con("elevation", "elevation", "", "VALUE > 2000")
outCon.save("C:/sapyexamples/output/outcon.img")