Hi there,
I am not being biased because I own a fair few tanks including another externally filtered (Fluval) but Eheims are the best. They are well designed and I have not had a single problem with mine, they are much easier to prime than others also. They are quiet as a mouse, most canisters are mind you. I would go Eheim if money isn't much of an issue.
I can't advise you on which model because you haven't stated what will be in the tank. A small shoal of Pygo's would requite more than a single Serra. I would guess reds because you are English and others are hard to find without organising a trip. For a shoal of Pygos I would reccomend a better filter than mine, even though my tank is a little bigger. The fish inside is only small and will not grow fast.
Hope this helps mate.