All 4 are great, but my choice would be the 2000s probably. They were definitely the most formative years for me with videogames.
A ton of my absolute favorites. My top 3 RPGs, with Symphonia, Baten Kaitos Origins and SMT III.
Wind Waker, Path of Radiance, Viewtiful Joe, Minish Cap, Mario Galaxy, Hotel Dusk, Kirby Air Ride to name a few more.