I am rather concerned over the fact that you have moderators laughing about the situation and worrying about how many emails you would have to send, as if it's some sort of great inconvenience, to notify the community of members of fact that their accounts have been compromised.
I'm willing to bet that a large sum of those 374,498 users, have no idea mrexcel.com was hacked. For those users who infrequent the forum, forgot they had an account, were on vacation or otherwise just havent logged in during that period, then they have no clue. For all they know, some script kiddy could be browsing through their private email as we speak.
A small banner at the top of the website, which I should note didnt even advise users to change passwords until Kyle123 and I put up a stink... and you consider that "adequate"?
@AliGW, do or don't, its on you at the end of the day. I think this thread already makes it evident why should be changing your passwords.