I have a Wii and a PS3 now and bought both well after they were released. I plan to do the same with the Wii U and the PS4. I like waiting a couple of years to save money on price drops, used games, player's choice and greatest hits releases, and for Sony, slimmer cases. I still have a long list of PS3 classics to get through in the meantime, so it's no hurry.
As for the Xbox One...yikes. I prefer PS exclusives like Infamous to Halo and Fable anyways, and Microsoft's E3 debacle did nothing at all to sway my mind. Ultimately it's the used games thing that kills it for me. I haven't bought a console game brand new in years which has saved me hundreds of bucks in the long run.