I have thought for a while that there would be 3 trends in terrorism that would start to emerge as terrorism now seems to be some extremist asshole's preferred method of doing business. The London attacks have shown that I was right about the first one:
1. More terrorists will now come from places like India, Bangladesh, and Pakistan. This is occurring now. In western nations, the U.S., Canada, across Europe, desi are a quickly accepted minority, especially in big cities. As more people come from the sub-continent, our comfort level with them grows. This can work against us though. There are many muslim in that region, and some of the more extreme forms of Islam come from that area. Consider, for example, the Deobandi form of Islam, which is what the Taliban practiced. It is Indian in origin. I believe that terrorist groups will work to use our comfort level against us. This will in future manifest as muslims from further East acting as terrorists. In several years we will see people from Malaysia, the Philippines, Indonesia, and other countries that are to western eye indistinguishable from Chinese people as terrorists.
2. Terrorists will attempt to sneak into the US across the US - Mexican border. Again, in an attempt to use our own perceived comfort level against us, terrorist groups will try to move operatives across the US/Mexican border to infiltrate the country. I realize this is by this point well known, but it does bear keeping in mind, especially considering the amount of talk given to offering amnesty to illegal immigrants, and allowing Mexican truck drivers to travel across the US without special permit requirements on the US side. It only takes a few people who look enough like they are from Mexico driving a few trucks of explosives into middle of America to cause widespread chaos.
3. Eventually, groups beyond our borders will employ the idea of "the enemy of my enemy is my friend" and groups like Al-Qaeda will look to tap into the domestic groups like the ALF to attack targets on this soil. I feel it's only a matter of time before these lunatic nutjob Animal Liberation Front people feel that they can further goals by getting money, training, and supplies from larger terrorist groups, and attack something big to try and make a point. Again, it works because we are complacent about your average white granola-eating hippie.
By hitting us where we're most complacent, the terrorism has its greatest effect. It makes us wonder who we can trust and cannot, forces us to question the people on our very block, and strikes at the root of those freedoms that make us a truly great country.
Anyway, I just wanted to put these out here and foster some discussion. Let me know what you think.

Two very interesting pieces of foreshadowing, that I read/viewed several years ago, and I thought were chilling...which have both turned out to be relatively true.
1.) Tom Clancy's novel, Debt of Honor. If you folks haven't read it, at the end, there is a chilling event that closely mirrors the events of 9/11. I remember reading this novel during either my freshman at Pitt, which was in '94. So, it's a ways before 9/11/01. I often wonder if the terrorists (Mohammed Atta and others) had read that book, and used it in their planning.
2.) The movie The Siege, with Denzel Washington and Bruce Willis. It's about a cell of Muslim extremists, that attack New York and create havock, and the military basically takes over the city, in response. This is no longer a far-fetched movie like I once thought it was when it first came out, and the quality of the movie isn't the greatest as far as accuracy or feasibility, but with recent events, it's become a bit more believable to me. The movie came out in 1998, and I'm not so certain that Edward Zwick, the director, was not thinking ahead when it came out. But, I'm not Roger Ebert, so I'll hold off on critiquing it further.
I just wanted to see if anyone else had made those connections, or maybe others that I've not mentioned? I agree with Maurice, though. The immigration from Mexico greatly concerns me, the crazy extremists groups are a concern as well, but the cells that hide from within the norms of our society are the biggest, scariest threat that we seem to be facing. How to confront them, well time will tell us the best way. But, I think we're holding them off, at bay, for now. I don't think that will work forever, though. And I am under no allusions that we've seen the last of the terrorist attacks. The bastards will be back for more blood.
What do you suggest? A sterilization of our religious freedom? I'm open to ideas!