R/B/W Burn deck I'm cooking up to get into Modern at my LGS.
Mainboard:
4x Vexing Devil: Getting either 4 damage or a 4/3 for one mana is just awesome.
4x Goblin Guide: Obvious. Have one atm and am running Hellspark Elemental until I get the rest.
4x Monastery Swiftspear: I love this card. Often times i can go turn 1 mountain swiftspear swing for one, then turn 2 Blood Crypt Bump in the Night Lava Spike swing for 3. Bringing my opponent down to 10 on turn 2 is pretty awesome.
4x Eidolon of the Great Revel: This card saves lives. Once I get my opponent low enough in life , he almost acts as a soft lock, making it nearly impossible to deal without dying or taking alot of damage. I find its best played once my opponent is down to 10.
4x Lightning Bolt: Obvious
4x Lava Spike: Helps to clock my opponent
4x Bump in the Night: Sucks that its only at sorcery speed but its awesome that damage prevention doesn't work on it.
4x Rift Bolt: Obvious
4x Searing Blaze: Works nicely with our fetches. Once you have one in your hand start to leave fetches on the field so you can trigger Landfall
4x Skullcrack: Great to clock my opponent but really shines against lifegain
4x Boros Charm: Great card and the reason we splash white. All three abilities are relevant; it can save our Eidolon's or let our Devil's and Swiftspears swing for double. And four damage isn't bad either.
Sideboard:
3x Inquisiton of Kozilek: Great disruption against most decks; getting rid of an important card from their hand is often worth the first turn.
3x Wear / Tear: Mainly for Leyline of Sanctity but can also work for Affinity
2x Dragon's Claw: For the mirror
2x Smash to Smithereens: For Affinity and Pod
2x Ash Zealot: For graveyard decks. Getting a first strike haste bear is also awesome for RR
2x Rakdos Charm: First ability can help neuter Goyf and graveyard decks, second helps against Affinity, and third is a nice burn spell against weenie/token decks
1x Rain of Gore: For lifegain decks. Was experimenting with Leyline of Punishment but it sucks to get a dead draw when its not in the opener.