I just finished Spin by Robert Charles Wilson.

Spin starts out with the earth being encapsulated, and ends with a race to emigrate to another planet.  In between, it follows three people tied together by their history.  Two are rich - a brother and sister  - and the third is the poorer son of a family friend, who hangs around.  They witness the encapsulation as kids, when the stars disappear one night, and the genius brother gets heavily involved in figuring out what happened.  There is a mostly non-consumated, very slow and contradictory relationship between the other two.

The book works on a number of levels - the characters are believable and interesting, and what has happened to the Earth is intriguing and makes for an interesting background.

Some of Wilson's other books suffer from being too cerebral and reading very cold, making them hard to feel really involved with.  You can feel the same thing around the edges of this book, but it manages to overcome it in the end, making it one of his most effective.