I am an ole timer and yes I did develop some sites that you so much dislike because that was what was done then. The browser war period was an interesting as well as frustrating time back then due to the evolving and revolutionary way things were done. The browser developers all thought they knew the best way to do things and pushed hard to attract users. And guess what we still have to jump through hoops to get web sites to work in each browser albeit a lot easier today than yesterday. There is a saying 'to be old and wise, first you need to be young and stupid', maybe IE is a little wiser now with version ten available.
As for your request I think you have answered it yourself. When you settle down you may like to look at the new html5 file api. Does it have to be an excel file? Why not a csv file or even xml for that matter. You do not mention where this excel file is, server side or on the clients machine.