I've built many barrel stoves over the years, both from Vogelzang and U.S.Stove.
Yes, definitely line the bottom barrel with fire bricks. I usually place some sand in the bottom so I can level out the fire bricks and also run a layer of fire bricks on both sides too. Doing so will not only help with longevity but also assist in keeping the ash hotter and the embers glowing longer so it is easier to catch a new load of wood for a continuous fire.
The single barrel stoves are great cheap heat and the optional cook top plate available from Vogelzang http://www.vogelzang.com/browse.cfm/hot ... /4,34.html
is a nice addition if you want to cook or add humidity to the air with a pot of water.
I personally like the double barrel stove kits for serious heat and better efficiency from the wood fuel. You can still install the optional cook top to the top barrel too. Depending on how much heat you really need, you may have to add additional air intake for a clean hot fire. I usually install the barrel door kit with the 2" bottom hole on the bottom and leave an air space between the hole and the fire brick to facilitate a really good draft. You can get some 2" threaded black iron pipe and install a draft closer on the end for draft control if you want to get fancy. But the standard slider draft should be sufficient for most applications.