So here we go, into the active period of the 24th solar cycle.
As does Punxsutawney Phil watch for his shadow to declare the coming of spring, a similar bucktoothed semiaquatic mammal- the Astronomer- watches the high latitudes of the sun* for the tell-tale reversed polarity sunspot. When the first reversed spot appears, that is to say one with the opposite magnetic polarity as the previous cycle's sunspots, then the new cycle has begun.
The past few years, ever since 2003 in fact, have been especially quiet, even for inactive years. However, we've already seen some powerful events in this cycle (though luckily, not aimed at earth), and we don't even expect the peak until 2012-2013.
The actual effects of these storms can be intense, but we are usually shielded by our planet**'s magnetic field. Which, to not mince words, has been weaker than usual. What we can expect to see are interruptions of the power grids, communications systems, and satellites. For instance, the Turn-of-the-Millenium flares caused a 6-day blackout in parts of Canada, and also caused disruptions in inhabited areas as well.
The worst-case scenario- perhaps a 1/500 chance- is a storm like the one we saw in the late 1800s, which accounts say fried telegraph wires and caused auroras in the Caribbean.
More likely, we'll have a few satellites get cooked (the GPS in particular is built of rather old devices), we might see a few communications breakdowns*** and we will most likely see a major blackout or two.
Since everyone loves a good panic, just imagine the worst-case scenario, which could be something like a very powerful flare at just the wrong time hitting the US, or Europe, with enough power to short out the whole power grid. More likely than not, some places would be back in only a day or two. It's just that others would most likely take rather longer than six days to get to, let alone reconnect.
*For safety reasons, please do not attempt without squinting.
**Earth
***Which will always be the same, and may cause some loss of sanity.