I bought a Miller helmet from
www.cyberweld.com. I can't recall the model (top of the line plain black hood, no autographs or painting) but it seems like it was around $220. I had a tool tent cheapie once and this Miller helmet is SO much nicer. I do a fair amount of welding from time to time, both steel and aluminum and I really like the shade and sensitivity adjustments. The delay setting is handy, too.
My theory is to buy a good one once and take care of it, and it should last me forever.