I knew Josh hommie started queens of the stoneage around 2000
and they are still going.
Plus he started a new band with David grohl(foo fighters/nirvana) and and John paul jones(bassist of led zepplin) called them crooked vultures.
Also I would nominate the white stripes, for being the most kickass 2 person band ever. These guys make alternative your favorite genre. Think seven nation army.
If we are talking about the 00's then I nominate Alice in chains for coolest comeback.