i voted
- for fractal phoenix or quinted-spirits+shields
- for lava golems, great!
- unstable gas with fire mark, how nice
- poison-bolt is so nice to play and very offensive, incredible
well, i voted for exactly the same elements, but with slightly different reasons
aether - yeah, fractal phoenix or even fractal brimstone eaters. Pretty much, fractal helps cheap rush decks, and fire practically specialises in cheap rush decks.
earth - lava golems, EQ (so pillar control, permanent control, creature control, what more could you want?), heavy armour to give those low hp creatures a boost.
air - well...air + fire is just insanely awesome creature control. you've got potions, fire bolts, fire storm, eagle's eye, shockwave, and air has fog shield, probably the most amazing shield for a rush deck. So you can go with a gas combo, a control deck, or just splash some cheap air cards (shield, maybe shockwave) into a cremation deck.
death - this one is kinda obvious. Death has cards such as bone wall, boneyard, vulture, which benefit from the death of creatures. fire has cards wic cause the death of creatures. I sense a synergy...