I am building a presentation on leadership and characteristics and am
stuck on movie clips depicting these two traits 1. humility and 2.
being proactive.
Any thoughts would be great!.. Something funny also would work.

Here are some brainstorms.  If they do not do the trick, I hope they
give you new ideas...

Proactive

Roxanne - Steve Martin's character has a big nose.  He is in a bar and
is taunted by a big thug who calls him "big nose".  Instead of letting
the situation get out of hand or embarassing, he has the thug throw a
dart to determine how many better comebacks than "big nose" he will
say.  The thug throws the dart and hits the 20 mark.  Steve Martin's
character comes up with 26, taking the power away from his aggressor
and proactively diffusing the situation.

Braveheart - William Wallace's army was the first to defeat an English
army (with 300 heavy horse) by being proactive.  They made spears and
did not show them until the moment they were needed.  Also they
divided their armies and let the English think that most had run away,
only to flank them and acheive victory.  Finally, they laid down
tar(or oil or something black) on the battlefield to later burn the
enemy down with arrows of fire.

Three Amigos - In the climatic finale, the three amigos find
themselves with an army bearing down on them in a town filled with
seamstresses and old men.  How will they defeat them?  By making Three
Amigo uniforms for everyone in town! This gives the impression of an
army of Amigos that are just as crafty and good with a gun as the
original three.

Ray - Ray asked to be paid only in dollar bills.


Humility (tougher to come up with)

Schindler's List - At the end, after all he has done, Schindler falls
apart thinking he has not done enough.  He looks at his wedding ring
and his car and imagines the lives it could have bought and saved.

Cool Hand Luke - Luke (Paul Newman) is in a fight with Dragline
(George Kennedy).  Luke does not stand a chance against the
intimidating bulk and overwhelming strength of Dragline.  He gets
knocked down and gets back up. Gets knocked down and gets back up. 
This happens many times, so much so that the spectators become
uncomfortable and tell Luke to stay down.  But Luke keeps getting up.
Eventually, Dragline loses intrest and walks away from him.  Luke did
not win, but he surely did not lose.

Incredibles - The super heroes go back into society to humbly obey the
new law forbidding them to interfere with normal life.

Empire Strikes Back - Luke leaves before training is complete in an
attempt to save his friends at Cloud City.

You could also use a sports analogy to illustrate both traits...
Rudy, is the story of a kid with a slight learning disability who
wants to play football for Notre Dame, he does everything he can just
to be on the field for one play and becomes a symbol for the team. (He
is proactive and achieves his goal while never being arrogant at all).
 As a leader though he is only one symbolically.
http://www.filmjudge.ca/r/rudy.htm

In SWAT, Colin Farrel becomes a leader of a group of a misfit SWAT
unit under Samuel L. Jackson.  Jackson has swagger, but Farrel plays
it with some humility, there is some joking about his abilities, but
he doesn't really show off with them (except when Jackson tells him
to) and doesn't give up.  He takes the steps necessary to ensure he
has a future (his building of a strange contraption to break into
homes and storm them can be seen as a silly bit of pro-active business
that ultimately pays off (again somewhat comically)
http://www.filmjudge.ca/s/swatmovie.htm

Depending on your audience, you could consider The New Guy.  It could
be seen to be all about being proactive and about being humble.
http://www.filmjudge.ca/n/newguy.htm
Consider:   Dizzy Gillespie Harrison is tired of being a "blip" and
wants to become more important - he goes out and gets an attitude
(pro-actively seeking out a way to find his leadership skills).  Once
he's changed his style, he realises that he can be most effective with
a combination of his more humble self and with some of the new
communication skills he has aquired.  Being/showing yourself to some
degree rather than putting on an act is the part of humility that
makes a true leader.
The New Guy also has scenes which parody both Patton and Braveheart -
with Dizzy as those leaders...  I know it seemed a stretch, but almost
any film of this kind is likely to have good clips on your topic -
again, depending on the audience.
(It might have clips that work and some may prefer a contemporary
comedy to one of those that have done the same thing in the more
distant past. I think there are better movies like Animal House,
Revenge of the Nerds, even Goonies and their ilk that all have some
things about leadership.)

Ike: Countdown to D-Day shows both sides of the Humility VS Pro-active
coin in a leadership role, and may be inspirational to boot.
http://www.filmjudge.ca/i/ikecountdowntodday.htm

When in doubt - go with The Muppets Take Manhatan!  Can you think of a
more humble leader than Kermit?  Can you think of anyone else?  I mean
honestly, Kermit is probably one of the great humble leaders of our
time!

Have you considered Gandhi?
It definately covers humility and I believe being proactive too.