Is Bombay the prototype for future attacks upon US soil? I suspect that the answer is YES. I also suspect that the attacks will be just as effective in the US as they were in India.
The following points are most notable regarding this latest attack by Islamic Supremacists:
Soft Targets: The only relatively hard target was the local police station -- which they hit first in an (apparently fairly effective) effort to disrupt law-enforcement response. Other targets were as soft as possible -- hotels, private homes, religious centers, restaurants, etc. This multiplies the effectiveness of the attackers in a large metropolitan area by creating the fear that anyone and everyone is a potential target.
Low Tech / Affordable Weapons: AK47s, a few LMGs, and grenades. Dang! -- this is competitive with the DC Beltway Sniper in terms of affordability. The injuries wrought by such conventional weapons, although perhaps fewer in number than from a jetliner ramming into a skyscraper, are multiplied in their media effects -- injured (but still recognizable) bodies and great pools of blood have greater personal impact on the evening news.
Indigenous Elements in Assault Teams: Rumors report that Indians and British nationals were involved in the assault. As India is a former British colony, using these elements in the assault teams may have helped the attackers to remain unnoticed until they unveiled their weapons.
Multiple Simultaneous Assault-Teams: Greatly complicating the LE response was the use of multiple assault teams. This also multiplied the effectiveness of the terrorists.
Each and every one of these techniques can be used against the US. As superb as our Law Enforcement organizations are, they are not prepared to defend against this sort of assault.
One solace might be that American citizens have a high rate of firearms ownership and would be ready and willing to confront the terrorists directly -- without waiting for law enforcement response -- we the citizenry may be true first-responders.