So for Standard Defonition, Apple is the cheapest (with the $55 Apple
cable, you can plug your iPod touch/iPhone to your TV once you have
downloaded the movie; or connect your laptop to your TV via VGA or
HDMI; or use the $200 Apple TV).
Apple is also the cheapest for HD if you have Apple TV or an iPad.
Apple will not let you use your computer or iPhone for HD movies (but
will for TV shows you buy).
Most of us are nowhere near our monthly bandwidth limit. But, for
example, if you have Rogers Ultra-lite Internet with Rogers, you will
go over your 2GB bandwidth limit after a couple of movies (after that
it is $5 per GB).
In conclusion, unless your bandwidth limit is an issue (for most
people it is not), or you have Apple TV or an iPad, Sony PS3 is your
cheapest option for HD anytime on demand movies. However, the
difference in movie rental price is not high enough to justify alone
the cost of the $300 PlayStation.