For those of you who like Mountains. Honestly, this is probably what I'd play if Regionals were tomorrow:

2x Lavaclaw Reaches

2x Terramorphic Expanse

4x Dragonskull Summit

1x Swamp

4x Arid Mesa

3x Scalding Tarn

8x Mountain

4x Goblin Guide

4x Plated Geopede

4x Hellspark Elemental

4x Hell's Thunder

1x Goblin Bushwacker

3x Zektar Shrine Expedition

4x Blightning

4x Lightning Bolt

4x Burst Lightning

4x Earthquake

Sideboard:

3x Manabarbs

4x Goblin Ruinblaster

4x Doom Blade

4x Searing Blaze

2x Lavaclaw Reaches

2x Terramorphic Expanse

4x Dragonskull Summit

1x Swamp

4x Arid Mesa

3x Scalding Tarn

8x Mountain

4x Goblin Guide

4x Plated Geopede

4x Hellspark Elemental

4x Hell's Thunder

1x Goblin Bushwacker

3x Zektar Shrine Expedition

4x Blightning

4x Lightning Bolt

4x Burst Lightning

4x Earthquake

Sideboard:

3x Manabarbs

4x Goblin Ruinblaster

4x Doom Blade

4x Searing Blaze