I was reading an article over on IGN about how Netflix are dropping out of the game rental service. I got to thinking and thought that Steam (or any other Steam like client for that matter) should implement something like that. They are big enough to pull it off and in this day and age there should be somewhere for PC gamers to rent games from. The used/rental market in the PC community is pretty much none existent due to DRM. Every other platform has a decent rental services so why can't we. I believe a lot of people would appreciate a rental service for their PC. There are a couple services like this in place such as:
Gamefly, which by the looks of the game list for their Unlimited PC Play service seems to be a bunch of small and indie games.
Onlive has some bigger titles at its helm however that is a streaming service, so unless you have a fast and reliable ISP. They are not for you I would actually use Onlive if I had faster internet. But it takes ages to buffer a 20 minute YouTube video I dread to think how my poor little connection would cope with a fairly new video game.
What I suggest is the ability to download the full game as you would do if you were buying the game out right. The you pay a fraction of the price and you can rent the game for a day, a weekend, a week or a month with the price varying depending on how long you wish to rent the game for. Along with the ability to download rented games as you would purchased games, you would also be able to have your save games and acheivements saved to your account so you can pick up where you left off next time you want to rent the game or even if you decide to buy it. They could also do discounts for the games you rent as an incentive to actually buy game. So say save 10% when buying a game you have rented in the past.
I have another couple of ideas which are frankly quite simple. The first of which is about the Steam client browser. It needs tabs, simple as that. They have tabs on the in game browser when you open it up using the shift and tab, I don't see why they can't put them in the desktop client.
Lastly is something my brother found on Reddit and pointed out to me a while back. They should put in a feature like this. Basically add an option to do a quick and simple scan of your hardware and tell you whether or not you can run a particular game. It would be an expansion of the worded system requirement at the bottom of each game page.