Originally Posted by Retro Grouch
Given that choice I'd pick the 19-25. If your tube is on the big size it's harder to cram all of that tube into the tire caseing and you're more likely to pinch a piece of the tube under the tire bead.
If I couldn't get the 19-25, I'd buy the 25-30 size inner tube and I wouldn't worry about it one little bit.
I changed the tires on my hybrid from 32 to 25 for commuting and used the old tubes. Lasted about 2 weeks until I had a pinch flat hitting a pavement bump. Bought the smaller 19-25 tubes and the tires went together much easier and haven't had a problem yet. When the other one goes I'll replace it with a smaller tube.