cioran: How is bigfish? They're cheap as hell and have tons of adventure games but I don't know anyone that subscribes to that $6.99/month one game per month service.
First off, you don't even need to subscribe anymore. The $6.99 price tag applies to *everyone*. Just remember, to opt out of the monthly billing if you don't want to subscribe (you can do that during your purchase).
If you do subscribe, they will charge you the cost of one game per month giving you credit in return. But you're not limited to only 1 game a month, you can easily buy additional credits or pay for games out right.
Their support is top notch. Pretty much the complete opposite to that for Steam. These people actually want to help you and -- surprisingly -- can actually read and comprehend what you write.
In fact, the only real downside is having to opt out of the monthly subscription model as it still appears to cause some confusion.