GIGABYTE HAS TWO more boards in their G1.Killer line, both below the G1.Assassin. They are called the G1.Sniper and the G1.Guerilla.
If you recall, the G1.Assassin is an x58 board with an X-Fi chip, Killer Nic E2100, Overclocking buttons, and specialized power circuitry. As Lars said, a bit gimmicky, but it hits the market they aimed for, right between the eyes.
Sitting below that is the G1.Guerilla board, similar to the Assassin, but with only 3 PCIe 16x slots. Basically, it can do 3SLI or 3 way CrossfireX. It still has the Killer Nic, X-Fi, Nichicon amps, and more goodies, but loses 8 phases of power. In any case, it should still be more than enough for the overwhelming majority of enthusiasts.
A little below the Guerilla is the G1.Sniper. If you look at it, you probably think it is the same as the Guerilla. That is more or less the case, but instead of the full X-Fi chip, you get ‘plain old’ 8-channel sound with the better Nichicon caps. Other than that, they are basically the same board, so pick your poison.
The G1.Killer line is aimed at a gaming and overclocking market. They are going for the full feature set, and basically hit the target. X58 chipset, lots of PCIe lanes, and just about every add on card you could want pre-integrated. Slap in a GPU or four, jack the clocks up, and off you go you junior killer you.S|A