The standard category of "eagle" includes hawks, falcons, kites, harriers, and other, similar raptors. Possessed of keen eyesight, strong flying capacity, and often either breakneck speed, keen vision, and/or tremendous strength, these avian predators represent some of the most majestic and powerful predators of the sky.
A protector druid from the Circle of Renewal can summon a desert hawk to serve as their companion (see Heroes of the Feywild). An arcane caster can gain a gallant hawk, who helps defend their allies (see Dragon Magazine), or a falcon, who helps them hunt through its eyes (see Heroes of the Feywild, pg. 142). Beastmaster rangers (see Martial Power) may have a "raptor" companion, which may be an eagle, falcon, or hawk. Those with the Animal Master (Dragon Magazine #399) theme may also have a minion hawk, falcon, or eagle, to help them.
Familiars may be helpful for more than just arcane casters: if you'd like to give any character access to the "Arcane Familiar" feat, it can help reinforce the idea of a bond with a particular animal, and can perhaps add some robustness to your Animal Minion, if you are also an Animal Master. In a setting like something from The Golden Compass, each character may have their "daemon", representing a part of their soul given animal form, regardless of their arcane abilities. Eagles can represent arrogance, pride, and nobility. Hawks fit a similar mode. Falcons are more for speed, agility, and ranged capability (such as bow-users).