two inches might not seem like much, but its actually a 20 gallon difference(when you consider that its only 2 inches but 96 inches long). The 96x26x25 should be 270 gallons, the 96x24x25 is approx 250 gallons. If the price isn't much more i'd opt for the 270
I doubt there would be a significant difference but might want to consider price of stand. Especially if you go furniture grade. Also if you go 26" wide it gives you a bit more flexibility for space under stand. You could fit a standard 120 under tank for a sump.