I'd say what makes the threat so alarming isn't it's current configuration, where it does not readily infect humans. I would say it's propensity for mutating, the contagion rate of this type of influenza, and the effects it has on it's human hosts that make it such a big scare.

That this strain would tend to adversely effect younger, healthier people by triggering a cascade of overwhelming immune response that seriously compromises the lungs, and that this virus doesn't just attack the respiratory system but readily infects other organs, including the brain, liver and heart, and damages them severely, make this a particularly noxious bug. Human influenzas are extremely contagious, and the way they attack the body by forcing healthy cells to manufacture more of the virus until the cell dies is pretty efficient. The virus itself doesn't do any work, it fools the cell into doing it all.

If you look at the 1918 outbreak, something that isn't so popular are the after effects, a particularly nasty encephalitic infection that came on about 3 or 4 years later in people who were infected but survived the respiratory attack, only to succomb to a vegetative consumption in the 20's as the virus slowly ate their brain.

Anti-virals like Tamiflu only postphone the pandemic, they don't immunize you against infection, they just temporarily block or inhibit the virus from taking over your cells. It is only effective in your system for a little while, and the timing of the dosage is critical to effectiveness as well. Once you've dosed and it wears off, you are just as susceptible to infection as you were beforehand. It will take 6 to 8 months for a vaccine to be produced once the virus mutates; the current vaccine will likely not be effective against a mutated human host strain. Think what happens to our civilization if people refuse to function to keep it going for 6 to 8 months. Yeah, I kinda like the idea of being thrown back in time for a bit too, kinda like the end of that Kurt Russell movies Escape to LA, but realistically we produce one heckuva waste stream these days, and if the sewage treatment plants stop functioning and the garbage doesn't get collected, well, things get very simple very quick. We run the risk of other more recognizably nasty diseases becoming a big factor now as well. How many of us have a big check valve at the main drain from our households, so that when the sewage system backs up it doesn't just start flooding into our homes, which I've seen happen more than once.

Now, I ain't trying to play chicken little here. I got more pressing issues to worry about right now just like the next guy, and my finances are just as finite and I am required to prioritize my needs, and I am not going to go hog wild right now preparing for a perceived threat beyond my general preparation for surviving in this day and age. Realistically if the flu did go off now, I would be hard pressed to avoid being one of it's statistics. I do think, though, that knowing what I am up against helps me to be prepared for it a little better. Our first tool of defense is always knowledge.

Were I to get stuck out in the open where I had to go be amongst the public during such an event, I would be looking to grab a few good tyvek suits, a full face motorcycle helmet, and a few goodies from the local hardware and electronics stores. Those ought to be reasonable, maybe the tyvek might be a bit of a challenge, so it pays to locate a supply nearby now and keep it in mind if the time comes.

That's about the extent of it I reckon.