Some time ago we discussed the merits of a used 997 compared to a new Cayman with the upshot that (in the UK at least) 997 prices were too strong. Anyway, I just had a gander at Autotrader and 997 Carreras are starting at Pounds50k now. And the S falls harder still - perhaps because it outsells the Carrera by about 3 to 1? For example:

2004 PORSCHE 911 S 2dr [997] Carrera Coupe,
28,000 miles, Porsche 911 (997 C2S), registered 15 October 2004 Manufacturers warranty remaining until October 2006. Plus extra years manufacturers warranty until oct 2007. Kept in underground garage since purchase. Tracker monitor fitted and subscription paid until 08/05/2007. Up-to-date with all Porsche recalls. 28000 miles, mostly motorway miles. Midnight blue metallic paint. 19" SportDesign alloy wheels, with colour central decal. Michelin ZR1 tyres, new set of four fitted on 13 April 2006. ParkAssist rear parking sensors. 6 speed manual transmission. Multi-function steering wheel. Climate control and heated front seats. SportChrono pack with PASM (Sport mode, changing suspension setup). Black leather interior and dashboard. Adaptive sports seats. PCM with satellite navigation and telephone module. Home mode lighting option. 4-disc CD changer in boot, 1 disc CD player in PCM, and 1 disc DVD player (used for sat-nav). Bose 13-speaker sound system (350 watt) with surround sound, audiopilot, and other features. Pounds55,000. ono

In 6 months, I think things will be closer still and a 2 year old 997S would be very tempting over a new Cayman