Bloody hell, this is a tough one.
Will start by saying Martin Crowe, I've always thought, could have been so much better than he ended-up being. Like so many Kiwis, suffered injuries that reduced his potency and shortened his career. Crowe's career average is dragged down significantly by poorness early and a little late, but for the overwhelming part of his career he averaged
54, scoring heaps of runs against everyone and anyone. Now, this numbers just 57 games but as I say, I'm near enough certain it'd have been considerably more but for injury.
Graham Gooch, on the other hand, was the first cricketer I truly idolised. Not surprisingly, this came in 1992, right smack in the middle of the time when Gooch was in one of the best periods of form any batsman in history has ever enjoyed (between his first Test of 1990 and his first of 1994, Gooch averaged
61, scoring heaps and heaps of runs off good bowling and bad alike). Gooch's career up to then had been fitful (he averaged 39, which is highly impressive, between 1978 and 1988, before a horror 1989 inspired his late scoring spree - however, this was if anything a disappointment, as he scored most heavily against the strongest attack he faced in this time, West Indies, and failed to cash-in as he should have against the weaker attacks). Gooch is one rare case where I feel a (relatively) small period at the end of a career seriously comes in level with a much longer one earlier (between '78 and '88 he played
66 Tests, and this would've been far more but for Rebel tours and the odd missed series; then between '90 and the opening Test in '94 he played
35), because of the fact that the latter one was so sensational.
Nonetheless, it's impossible to say Gooch ever matched Crowe's proficiency before that late-on period. They both did very well against West Indies, but Crowe cashed-in far, far more effectively against the less extraordinary attacks. Yet Gooch played on for longer, stayed fit (not to Crowe's discredit that he didn't obviously, but inescapably fit > not fit) and in the end probably contributed more to English cricket's wellbeing than Crowe did to NZ's.
I'll have to go Gooch, but I suspect if I was a Kiwi of my own age I'd probably go Crowe. Gooch is merely what I have known and loved, while Crowe has generally carried a fair air of mystery - I've only ever seen him bat a handful of times.