Yes it was the last episode of the anime, the whole slideshow of the trip to America was actually a HUGE story arc in the manga. In fact the manga continues from where the anime left off and goes into MUCH MUCH more detail about America and what happens afterwards. There's about 20 or more volumes of it out right now.
The show itself did a good job of staying true to the manga up until the last episode where they tried rushing in too much and killing most chances for a second season.
on an unrelated note I thought the fact that the band Taira was in, Heroes, playing music by The Pillows (You've heard their stuff if you've seen FLCL) was pretty cool.