If God exists and you worship anything in his place, then that thing is a false god and you are an idolater. But if God does not exist, and you worship anything at all, then you are also an idolater. For idolatry entails worshipping something unworthy of worship, and if God does not exist, then nothing is worthy of worship.
Now atheists typically pride themselves on 'going one god further.' Thus they typically say to the Christian,"You reject all gods but the Christian god; we just go one god further." So, consistently with his atheism, an atheist cannot worship anything. If he makes a clean sweep with respect to all gods, then he cannot make a god of sex, power, money, science, the Enlightenment, the state, the withering away of the state, the worker's paradise, the atheist agenda, nature, himself, his mortal beloved, not to mention golf and Eric Clapton.
A consistent atheism may prove to be a difficult row to hoe. The atheist will be sorely tempted to fall into idolatry, making a god of nature, for example, as some environmentalists do, or of science, or of the enlightenment project, or of the state as with totalitarians left and right, or of the 'crusade' against Christianity or religion generally. The atheist will also want to avoid nihilism, the denial of value to everything. The atheist must find meaning in a world in which nothing is absolute, nothing holy, nothing worthy of total commitment. Nice work if you can get it.
Can one live a meaningful life without God and without idols? Without an Absolute and without illicitly absolutizing anything relative? I don't know. I suspect not. I suspect the atheist will fall into some sort of idolatry and end up worshipping nature or the state or something else obviously unworthy of worship.
Can an atheist live life to the full, keeping up the strenuous mood, falling neither into idolatry nor into nihilism? The great American philosopher William James (1842-1910) would, I think, demur. In "The Moral Philosopher and the Moral
Life,” we read:
The capacity of the strenuous mood lies so deep down among our natural human possibilities that even if there were no metaphysical or traditional grounds for believing in a God, men would postulate one simply as a pretext for living hard, and getting out of the game of existence its keenest possibilities of zest.