Originally Posted by Lightning Strykez!
Actually I agree with much of what you said, especially what I bolded above.
However, Halle Berry was the top billed actress in the credits. It's her face that was pushed to the front of all the marketing materials, posters, promo and trailers, etc. Yes, it was an ensemble film series, but when people look back it is Hugh and Halle's star power that dominated the most.
Halle has always been the first billed actress in the X-men series. Was the this "lead actress" in X1 and X2? No, for the first films, the "ensemble" is billed alphabetically - Berry, Janssen, Marsden, Romijn. Patrick Stewart must have had it in his contract that he billed first in the films (which changes once the contracts had to be renegotiated). Anna Paquin receives the "and..." credit which is a "prestige" credit reserved for a respected or know actor.
Berry most likely had it in her X3 contract that she receive above the title billing with Jackman (this may have been one of the reasons her contract took so long to negotiate).