You've got to be kidding! 1394b (Firewire 800), Intel 925/915 chipsets, SATAII (and stuff like NCQ on the ICH6), PCI Express, DDR2, WD Raptors with 10K spindle speeds in SATA, Opterons with the on-CPU memory controllers, DDR3 RAM/improved GPUs on graphics cards, CPU cache going up to 2 MB on both Intel (EE) and AMD (FX), Nocona and Turnwater, dual core, BTX's new thermal standard to allow even faster components....and that's just the tip of the iceberg.
Speed doesn't come from CPU GHz alone.
Of course, "technically, computers haven't changed much..." if you compare them to ENIAC :)
(BTW, clock speeds aren't stuck at anything. Heard of Moore's law? Current highest Intel CPU generally available is 3.6 with 3.8 and 4.0 GHz due out soon.)