I really like the NX class. As Mage said, a good, compact, efficient design. I've read some cool articles on the thought that went into the design process by the Trek folks, taking some additional inspiration from the WWII Lockheed P-38 Lightning (the "Fork-tailed devil"). In Universe, there is much logic in (and no problem with) revisiting an earlier, successful design configuration for a new class of ship. After all -to expand upon what Tiberius & KingDaniel have said- we didn't hear much uproar that the Sovereign design was clearly descended from the Galaxy that was a modified Excelsior design that was an altered Ambassador, etc.... and all the way back through the previous classes that were a cigar shape with a saucer over the front and two roughly cylindrical engines in back of it. The NX is a sweet design!
I know that some folks hoped to see a unique, primitive design that was something noticeably different from the familiar Starfleet configuration of components, but I am pleased that we got a ship that looks like it is 'part of the family'. 'Enterprise' also gave us some other "new" ship designs (the Vulcan ring ships, Andorian warships, ...) that satisfied my interest in seeing recurring 'different' Trek 'wessels'.