I have a 100ltr & 120ltr and recon they're the ants pants and at a fraction of the price of other brands and come with a 12 year guarantee.
As far as the ice packs are concerned, I find that they aren't much use for anything other than a day trip. Stick with the block ice as previously stated. If you would like some though, they do include them free with your ice box purchace.
They also sell these on Ebay and as long as you are aware of the price inc. delivery direct from Techni Ice compared to price inc. delivery from Ebay, and you are patient, you can pick up a real bargain. I picked my 120ltr up for $175 & 1he 100ltr for $103 inc. delivery.
This free eBay Auction Sniper Service sight might help http://www.gixen.com/