The Year's Best Science Fiction: Twenty-Fifth Annual Collection
If these were the best stories of 2007, I'm afraid it wasn't a very good year. More likely, I just don't agree with Mr. Dozois' choices.
I picked this up at a discount store for $5, and for that, it's reasonably good value for money. There's a lot in this, including a (numbingly detailed) review of the year's magazines and SF news, and a long list of runners up. Almost 700 pages of SF info.
Unfortunately, many of the 32 stories included just aren't very good. Dozois has included many of the big names in the field, but they don't always measure up. None of the stories are really bad, but there are quite a few in the 'eh' category. And while he generally avoids all out fantasy, not all the stories are really true SF.
Still, some of the stories were very good. My favorites included:
"Against the Current" by Robert Silverberg. A time travel story that doesn't really go anywhere, but works regardless.
"The Merchant and the Alchemist's Gate" by Ted Chiang. Not very SF, but a good story.
"Steve Fever" by Greg Egan. Longer than it needed to be, but a nice exploration of a concept.
"Tideline" by Elizabeth Bear. A surprising but touching story of duty and devotion.