^Speaking of jumping into new universes, I recently read Alastair Reynolds's Revelation Space, and liked it enough to track down the other two books in that trilogy, Redemption Ark (which I'm currently reading) and Absolution Gap. There are other tales in the same universe, but apparently those three are the main trilogy, so I'm starting with them (even though Chasm City came out between the first two). Apparently it's regarded as a somewhat dark or "noir" hard-SF series, but I actually find it more upbeat than some; there are dark situations, to be sure, but the main characters tend to be relatively decent and sympathetic people, which to me gives it an optimistic flavor. It's not a dystopia where everybody's awful, just a world where both good and bad things happen and where most people are acting for what they believe is the greater good even when they disagree profoundly about what that is.
Just a word of warning, as a trilogy, those three books are pretty loose. In particular, the third book isn't the epic finale you're expecting, more of a side story that winds its way into the narrative from the previous two, something which a lot of people find disappointing.
I do wholeheartedly recommend all the other books in the same universe, though, particularly the short stories. The Diamond Dogs / Turquoise Days novella pair is especially phenomenal, and the final short story in the Galactic North collection is much more the epic ending that Absolution Gap doesn't manage to be. (Not directly related to the trilogy, but chronologically after it, and I found it more satisfying as a conclusion.)