Ok, regional - I agree...half each, eh??
From certain countries, you do need a visitor visa - and it probably is 90 days. From KitKat's UK address, the answer is No!.
The green coloured form completed on the aircraft (for INS) is an I94W - not an I94. The 94 is given to those with visas (and is white) - the 94W is given to those without visas...hence the name "Visa Waiver Scheme".