if only we could make IE burn. unfortunately enough it only has something like 96% market share. firefox has 5%, so its worth coding for. but Opera has something like 0.9% with all the other browsers sharing the other .1%. i'm not sure its really worth making sure websites will look ok in opera as hardly anyone actually uses it.
the only people i know who use it only use it for testing purposes - same reason they keep IE on their systems.