There are many types of companies in this world and what you described is not uncommon although for a while it looked to be a dying breed. With the decline in the world economy, it's well documented that companies have made up for reduced staffing with more work, and even historically great places have been called out for becoming harder working these days.
That doesn't mean it has to be this way. You can decide to go elsewhere although you may find it more different than you think. Part of the reason people keep working at companies that drive hard is exactly that level of drive. It's not to say you want to be woken at 3am but in a lax firm some people get bored and actually crave the craziness again.
From what you described it sounds like this isn't working for you and isn't giving you a good balance. Thus you have to decide; is there a compelling reason to stay (i.e. great work, great pay, great advancement) for a set duration or is it time to move on. Personally I've found times to endure madness but always feel you need a balance and that's up to you to create, so if it's not working, don't rant, fix it. But that's easier said than done, and much easier said when you have no real dependencies to worry about.
As a final thought I will offer you this -- agencies tend to work longer than clients, they also tend to be more diversified and move quicker. Client companies go to agencies to do things well, fast and without ramping up so when they want more, they expect it to happen and the agency doesn't want to say no. Of course there are exceptions, I've known agencies to fire clients for pushing their people so if you want something more balanced, you may have to look but it does exist.