Hi there. To be honest at wide angles, IS is pretty redundant as it's just a gimmick for people to 'drool' over it. IS is more essential for tele lenses. The 17-40 is pretty gd for a walkaround on a 450D else u're using full-frame.
I'm a beginner, planning to buy this coming pay day an EOS450D but don't know what lens i need to buy, saw that you are using 17-40L lens, may i ask whether you can recommend this lens for a beginner like me? Is IS important with this range?