Big Mike - If you've got newish shocks you'll be fine with just springs, go for eibach though, miles better than others.
Guv - If you just want to lower it and leave it i'd probably just get a suspension kit (shocks and springs). They will work out cheaper than coilovers for definite, koni kits are meant to be one of the best, weitec are good too.
Coilovers are good if you think you are going to want to change the ride height. I've got coilovers on mine and they aren't set stupidly low at the moment, I plan to keep the car for a while though so i invested the extra bit to give me more flexibility in the future if needs be.