There is no real standard per se — it depends on your requirements.
CSS image replacement techniques work well for titles that wont change - so column headers and navigation for example. Unless you have a server side script used to dynamically generate images based text - but that's a whole other thread.
As far as I know you cannot use JQuery for image replacement as such - well you probably can, but in tandem with CSS or Flash.
Personally I try to use as little image replacement as possible, keeping most text in section dependent CSS sprites if I have to.