The typical anarchist paradise is a communal society where everyone willingly pitches in to help each other. However, by definition, it involves no coercion or imposition of power. This means no justice system (at least as we currently understand it). Such a society only works while everyone plays by the rules. Any cheaters would prosper, accruing power to themselves with ease.
In our current technological climate, the stable - and therefore inevitable - situation is some kind of capitalist state like we have now. While it makes war, throws millions of its own people in horrific, abuse-prone jails, and transfers billions of dollars to rich corporations, there's no real other option. Violent revolution would merely institute a brief and unhappy transition period before the State gets re-established.
If we can’t change anything, of what political use is anarchism? Well, some anarchists don’t argue that we ought to destroy government and institute a new system, but – where possible – shrink government and limit its power so that it can't kill as many people overseas or prosecute the godawful War On Drugs. I’m fairly sceptical about whether these goals can be achieved but, unlike an anarchist utopia, they’re at least possible. In practice, this approach might more accurately come under the label of ‘minarchism’.Anarchism can still critique totalitarian theories in the same way that Marxism can mount an effective political critique. Sure, a communist utopia is impossible (for much the same reasons as an anarchist one) but that doesn’t mean Marx was any less wrong when he tore apart capitalism. Anarchist thought can highlight the places where subtle coercion occurs – places which would slip under the radar if nobody was looking for them. (For an example of this, see Crispin Sartwell’s wonderful notion of ‘squishy totalitarianism'.)
For an anarchist alternative to the State to be possible, our culture and ideas would have to have undergone fundamental change in a lot of ways. Until then, there is no permanent alternative. So let’s look for impermanent ones! Personally, I like Hakim Bey's Temporary Autonomous Zones as a practical anarchist utopia. They don’t have to involve a lot of people and can last for a few hours – perfect for boring afternoons.
Perhaps more seriously, we could apply anarchist principles socially and avoid coercion in our personal relationships. So many awful behaviours, from casual racism and sexism to straight-up violence, rely upon subtle mechanisms of control. We anarchists will never get the State to stop oppressing people – but we might just manage to stop ourselves.