TheNoobHolocaust on 22 April 2010
Wii - 4 years, I don't expect to see a Wii HD, Wii 2(we'll call it that even though I doubt it will be anything like the Wii) will release in 2014, at that point Nintendo will phase out the new best selling console of all time, the Wii.
360 - 3 years, I have a feeling they will begin development Xbox 720 roughly a year after PS3 catches 360 in sales, which has a good chance of happening next year, so Xbox 720 would release in 2013.
PS3 - 6 years, even when PS4 comes out, which I expect to come in 2014, Sony will continue to support PS3 and stretch its lifespan to 10 years.
