From the beginning?
The Wii. Late 2008 saw the Wii Fail presentation. The wii was not long before then in 2006. To be fair 24c3 the year before (so a year after) quite literally saw the first non GC related hacks happen around the same time.
The DS. Give or take the neoflash
http://gbatemp.net/threads/nds-rom-patcher-released.27468/ (September 2005), now Darkfader's work happened in January 2005 which was technically before the EU release (Japan had it in late 2004)..
The PSP.... May 2005 I believe was this and the stuff that would become the 1.00 firmware exploits. Never mind how long it took things to stabilise after that.
Also the PS3... that took a little while. Mid 2010 by my count for the earlier USB stuff which was good. The console hacking 2010 saw new years 2010-2011 have an explosion of things.
The 360 had the DVD mods which were great. There was also the King Kong homebrew mod that nobody could really use. JTAG came to the fore in the middle of 2009 though, for a late 2005 console.
As others have said as well give or take the PS360, though even there it could have been far better and there were some fundamental mistakes*, that go around saw the companies do a pale imitation of a real hardened embedded device. Do not get me wrong I would not have envied anybody that had to come up hacking the said go around, I certainly do not this current one, but that is a different discussion.
*the console hacking 2010 does well for the PS3 here. The 360's DVD stuff (a secure device in which the sole item that vets the authenticity of media also verifies itself..... madness) attesting to the 360's main failure, the
rest of it was not bad though (do note it is an old presentation and actually dismisses the thing that would later lead to the RGH family of hacks, as noted by the people that eventually made said hacks. Do also note that RGH, and some of the PS3 stuff, used techniques not commonly seen in console and embedded device hacking before then).