Okay, I just want to preface this by saying that I am truly content with my hawk familiar. Also, if this discussion annoys others, I'll stop. I don't want to break the thread.

That said, I like to talk about familiars as a mental exercise.
Madfox said:
The hawk has an incredible good spot check, which makes it a lot more useful as a scout then a raven.
This is very true. However, the owl shares this bonus (admittedly at night vs. the hawk's daylight bonus, but one could argue the merits of each circumstance equally, I think.) And an owl gives a +2 bonus to Move Silently as well. So with regards to the Spot check, the hawk is better than a raven, but on par with the owl, which also grants a +2 to a skill.
An other benefit of a hawk is more roleplaying wise and it is rather campaign dependend (so I doubt it has been taken into account when determining benefits). Hawks are accepted as a pet and less associated with witches and the like.
While this may be true, as you yourself said, roleplaying circumstances can never be used as a balance to game mechanics. So saying the hawk is more accepted, and thus should not get a bonus, doesn't work out.
Now I'm not saying that a hawk should grant a bonus to a stat like the toad. Obviously, the hawk is more convenient than the toad. Like the raven and owl, it is great as a scout, and can (if the wizard is willing to risk it,) deliver touch attacks much more easily as well.
However, when compared to the raven and owl, the hawk comes up short. An owl has low-light vision and a great listen check, and grants its master +2 to Move Silently. A raven speaks a language, enabling it to act in any number of tactical situations. The hawk...can fly. That's pretty much it.
Still...a hawk
is cool. Just not the best choice from a powergamer's perspective. It scores well because it's a flyer, but scores last among the other flyers.
