What do you guys use to keep your lunch boxes cool?

I use a medical ice pack like one you'd put on your head for a headache (Similar to THIS, seems to be pretty common. However, I've found that ice cubes tend not to last all day, and it takes forever to fill the bag with the small fill hole.

I've gotten much better performance by filling the bag partially with water, and freezing the bag as one big block of ice, however it's hard to get it to freeze into a shape that fits into my bag.

So, I'm thinking that maybe I should get some of those freeze packs, since a large block tends to do better than cubes... BUT...

Some of our hotels don't have freezers in the room (I'm sure you've run into this). In this case, I'd have to use the ice machine to fill my bag, and I have the associated problems with the cubes not lasting all day.

I can always swipe some ice from the galley, but that can be difficult during a day with 40 minute turns.

What do you all do?