A question only you can answer because the answer depends on the kind of person you are.
If you are the nostalgic sort, keep your Holdsworth as original as you possibly can.
If you are a functionalist, keep your Holdsworth and treat it to a set of bacon shifters and maybe clipless pedals.
If you like new stuff, treat yourself to a brand new bike - they really are better.
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My greatest fear is all of my kids standing around my coffin and talking about "how sensible" dad was.