With several services now letting you download movies and play them right on your TV, the DVD discs as well as the currently developing market of Blu-ray discs may be under threat. Today's video stores promise to offer near-instant delivery of hundreds of movies, including many in high-definition, all ordered up from the comfort of your couch. AppleTV, XBox Live and Tivo are currently the top contenders.

However, all these services require you to shell out several hundred dollars for special hardware first; they also demand some set-up, and rely on a fast Internet connection.

Blu-ray entertainment also requires consumers to spend a significant amount of money in players and high-def TV sets, but the format has the advantage to offer high capacities which mean more HD content.

Apple TV went on sale a year ago, but it only acted as a bridge for video and music to cross the gap between your computer and television. The upgraded Apple TV was released last January. It allows users to browse Apple's iTunes online store directly on a TV set. The addition of rentals quelled complaints about the previous buy-only service.

AppleTV is currently offering 1,000 movies for rent, with about 175 of those in high-definition. One selling point is that you can transfer Apple TV movie and TV show purchases (but not rentals) to a computer, iPhone or some video iPods.

Apple TV costs $229 for 40-gigabytes of storage that can store 50 hours of video, or $329 for quadruple the memory.

Microsoft's vision to provide entertainment through internet seems to finally becomes a reality through the Xbox 360 video game console, which offers the Xbox Live video-on-demand service.

Microsoft offers more than 300 movies for rent, about half of which can be viewed in hi-def. Including TV shows, Microsoft says it has more than 4,000 hours of content, while the company tries to attract even more content by making deals with more studios.

Xbox 360 prices range from $280 to $450, but the cheapest model does not include the hard drive you'll need to store the videos. The $350 Premium model has a 20GB hard drive and the $450 Elite ups that 120GB.

TiVo, the popular digital video recorder already in many homes is another device that can be configured to act as a video store in a box.

A deal with online retailer Amazon.com lets some TiVo users rent videos from Amazon's Unbox service. Since last July, TiVo owners have been able to use their machines to download directly from Amazon's library.

TiVo owners do need to configure their machines to sync with an Amazon.com account, and some older machines won't work. Unbox also can't be used with TiVo service offered through the DirecTV satellite provider.

Amazon has thousands of movies and TV shows on offer, although they are not in hi-def yet.

TiVo boxes come in many configurations and price points, from less than $200 to more than $600 depending on the number of tuners, the size of the hard drive and whether it supports hi-def. There is also a service fee that can be paid monthly or in a lump sum up front for the life of the product.

There is a price uniformity among Apple TV, Xbox Live and Unbox. Newly released movies cost $4 to rent, with hi-def versions going for a dollar more.

Other options for downloading movies to watch on your TV include the on-demand services cable companies are currently offering.

It is clear that in a couple of years, movies themselves are going to be downloaded and consumed differently than they are today, as soon as the internet connections become faster. For now, Blu-ray enjoys a good penetration and consumer awareness, according to a recent study.