With one of the most famous openings in classical music, this movement by Beethoven was revolutionary in the way it used a single powerful motto throughout. The music still has that power and is still popular today. The complete symphony of 4 movements can be found in miniature score form from Sheet Music Plus (US) or The Music Room (UK). You can also get the full scores of Symphonies 5, 6 and 7 in a Dover Edition from The Music Room.
You can download all the parts from mfiles for the first movement only: Flutes, Oboes, Clarinets (in B-flat), Bassoons, Horns (in E-flat), Trumpets (in C), Timpani (in C & G), Violins1, Violins2, Violas, Cellos, Basses. Note that Trombones, Piccolo and Contra-Bassoon only feature in the 4th movement for the symphony's climax.
Here's an interesting version on YouTube for your amusement, where Sid Caesar and Nanette Fabray brilliantly mime an argument to this very same 1st movement of Beethoven's 5th.