A couple of mentions, of variety and the positions of Butcher, Hussain and Vaughan:
For me it's this simple: Butcher has been an opener all his First-Class-career and Hussain has been a number-three all his. Vaughan was perfectly succesful at number-four and his limitations as an opener have actually been exposed last summer, several times he was caught behind the wicket driving on the up. Yes, he batted well in the second-innings' at the MCG and SCG last winter, but I thought elevating him to open in New Zealand was a mistake and nothing happened in 2002 to change that idea. Yes, Vaughan scored 5 centuries, but only one was chanceless, at The Oval.
Regarding variety of bowling; IMO variety is not as important as some regard it to be. Good batsmen aren't unduly troubled by a change of the pace of the bowling. On a green wicket under overcast skies, a fingerspinner is a waste of a place. In any conditions except a dusting, dustbowl wicket a fingerspinner is a waste of a place.
And right-arm\left-arm variation is pointless if the left-armer is a lesser bowler than a right-armer available.
It is as simple as this for me: you pick the bowlers who you think are most likely to get the best figures and make the biggest contribution to a win. If they're all right-arm seamers, so be it. It didn't do us any harm in 2000 when we had Cork, Caddick, Gough and White, because they're all good bowlers.