I got horribly lost in London today. I was accompanying a client to a pitch and admittedly our target was absurdly tucked away but… if I'd had a GPS enabled phone we wouldn't have walked in a huge circle!
I'm also sorely tempted by one of those 3G cards for my PowerBook (well the Vodafone one as they're the only ones to support Macs). GPRS via Bluetooth is ok, but rather slow. 3G data would make those delayed trains a bit more bearable but I'm not sure the Brighton area coverage is any good…