I am in same general opinion as Aaron......build it as how you are going to use it
That said I have become quite partial to modern components like 105/ultegra on classic frames. you get the advantages of a good gearing range, super nice shifting and breaking. You can get a full group quite reasonably from UK bike shops. It may require a cold set but that is not horrible
other wise if you are keeping it friction, go with the components you like campy or shimano or ??? but if you need gearing range, look for a triple
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Life is too short not to ride the best bike you have, as much as you can
(looking for Torpado Super light frame/fork or for Raleigh International frame fork 58cm)