There are a couple variations that can be made with the free white/red deck. The deck can be highly creature oriented or tactical spell heavy.
Cards that specialize in a theme (soldiers and goblins) should be culled out, since the deck would be hard pressed to carry any specific creature theme. Taking out Helm of Fortitude and Super Swift Boots right away.
Keeping the efficient creatures, creature enchantments, and spells, the deck starts to take shape:
Obsidian Golem x3
Dauntless Soldier x3
Initiate Soldier x3
White Knight x2
Guided Strike x3
Holy Strength x3
Silence x1
Berserker of Bloodridge x3
Goblin Fodder x4
Raging Goblin x3
Headfirst x1
Lightning Bolt x3
Seething Song x3
Threatening Lunge x3
With 2 spells to go, throw in some healing colorless cards and try it out:
Dragon's Claw x2
Variation example
Some of the less efficient creatures (Obsidian Golem and Berserker of Bloodridge) can be switched out for more crafty cards (Tactical Advance and Cleaving Might) or better cards from the free booster.
Of course, this is just one deck idea and the deck can either be a red deck with a few white cards thrown in or vice-verse.
Complete white/red list