My favorite features to talk about are the Spring Expression Language (SpEL) and the new @Async and @Scheduled annotations. That's because they have a lot of "wow" factor when I present them.
In a more practical sense (not that SpEL and those annotations aren't practical...I just don't use them quite as often), I enjoy using @RequestBody and @ResponseBody in my controllers and relying on message converters to work their magic in converting messages to and from whatever object I need to work with them as.
Of course, the
Java configuration option is pretty awesome, too.
