The only battery I found listed at Dell.com that will work with my Inspiron 9100 costs $194 and lasts almost less than 2 hours!
Other laptops now seem to be able to run batteries that might last 6 hours, depending upon the operation they're required to do in use (playing DVDs costs more energy than just typing documents in MS Word).
But the battery reviews of my recommended model are NOT good. Short life and overpriced for the lack of value.
Anyone else have any recommendations? (I usually DO use my laptop plugged into AC power, but the power bar is large and annoying to lug around.