[b0rsuk]

I really like Stars My Destination by Alfred Bester. It's not very long, but you can't accuse it of the lack of scale or vision. Has a very energetic protagonist, a conflict betwen Earth and colonies on outer planets, multi-national corporations, lots of imagination, swift action, very enjoyable writing style, and pretty good ending. Consistently pops up among top space opera or even just science fiction book lists.

Isaac Asimov's Foundation serries is not heavy on action, but it's a very good space opera, with vision and a great sense of scale. Even individual chapters can be a few decades apart.

You've said something about alien races. Neither of the books above features them in a meaningful way. So if that's important to you, try Ender's Game by Orson Scott Card.