Why do we need new games? Everyone knows Quake 3 attained perfection in 1999. It's a scientific fact.
But hey, 1999 was a great year. CPUs and 3D accelerators were powerful enough to run games like Quake 3 or Half-Life. All games released after that has just been about adding more fidelity.
Sound quality of music albums reached also a pinnacle point: we got great digital audio workstations with lots of tracks and good signal-to-noise ratio, and the dynamic range compression madness had not yet begun.
Windows 2000 was released, which is the other of the two non-sucky graphical operating systems Microsoft has released (the other one is Windows 7). Linux also got popular on the desktop.