Ditto here. 17" MBP (the immediate predecessor of this new one), and the battery's essentially permanent in there for me. 8 hours of text editing, iTunes, and compiling sounds fantastic.

Only thing I picked up was a second power adapter. Now one's at my desk, and another's in my bag.

Note that batteries for these things usually cost $129ish, so $179 for the swap isn't out of line.