People love firmware updates on the PS3. Why? They continue to add new functionality. While the most-requested feature, in-game XMB, still has not arrived, the latest update (2.20) included a number of new features, such as support for BD-Live, the latest Blu-ray disc profile. The interview notes that the PS3 is much more powerful than standalone Blu-ray players on the market, and that the "performance gap" won't get smaller any time soon. Because of this, Blu-ray discs can differentiate between players, and include "richer effects" on PS3 systems.
Future firmware updates will include 1080 deinterlacing and DTS-HD MA, much to the joy of serious home theater buffs. Expect updates to happen quarterly -- although the revised PS Store will break from that planned cycle.
While the most recent firmware is required to sign into the PSN and play the newest games, it seems as though firmware updates will be required for movie playback as well. In fact, the Resident Evil: Extinction BD includes an updater on the disc, for firmware 2.10.
Expect this trend to continue into the future.