Many speculate that higher intelligence is most likely to develop in two cases:
1. The species have dexterous appendages. This leads to tool usage, which leads to intelligence (examples: primates, octopuses, elephants).
2. The species are pack hunters. Working as a team and devising an attack/ambush strategy requires far more intelligence than prey who just flee (examples: orcas, dolphins, canines).
Considering that we probably developed intelligence due to our hands, we might actually be one of the more peaceful species (I know humans engage in pack hunting behaviour, but I would argue that that began AFTER we developed intelligence). A species that grew clever from pack hunting might be fiercely territorial and aggressive towards anyone outside "the pack" (Granted, to be able to build technology they would need to be quite dexterous, but perhaps selective breeding could improve appendages already available?).
The "Predators" from the Alien universe might not be too far off. Unless they completely abandon their biological bodies and psyches in favour of technological constructs.