My LBS - Silvester Brothers in Cove have been awesome from day one, just a shame that they don't stock/can't get a lot of the stuff I buy - they've never failed to sort out one of my 'little problems'
Wiggle - always been happy though current prices see me using them less
CRC - excellent service and keen prices
On One/Planet X - good service and some good deals
Spa Cycles - great on the phone and top notch service/delivery
Ribble - have been fine when I've used them
Merlin - very speedy delivery no problems
Dotbike - superb service and delivery
Corridori - great service even though I've not yet made a purchase from them
Rapha - service and goods excellent
Harris Cyclery in the US(erstwhile home of Sheldon Brown) - very helpful and good delivery
SJS Cycles - service, delivery and returns all excellent, but the postage costs for small items are eye watering
There's been many others but these have had most of my business, the only shop I'll never enter again is
Sigma Sports in Kingston, life's too short to tolerate attitudes like that.