I've known people who loved Iron Maiden and people who didn't care for them but I've never heard the complaint that the vocals didn't match the music. As a long-time fan, I happen to have liked Di'Anno as well, however, Dickinson replacing him is the key that propelled them to a greater level and, eventually, legendary status.
Even so, I can get that some people don't get into Maiden. I was the same way about Judas Priest. No doubt they are metal godfathers but I just never liked their sound all that well. I still respect them; if it wasn't for Priest and Maiden, a lot of metal music today likely wouldn't exist.
Back to the subject at hand, I've actually not heard of several of the bands mentioned by others. Some, I have heard of and don't care for myself. Others, I honestly never thought of as metal, even with my wide-ranging, eclectic view of the metal universe. But, the lines do get a bit fuzzy from time and time, even among bands I prefer and enjoy.
I think the main thing, for the OP and anyone else exploring metal, to consider is just that. Metal means a lot of things to a lot of people. There is a multiplicity of sub-genres and you ought to take time to give the wide ranging musical styles a listen. Don't paint yourself into a corner by taking a lot of time to identify what is 'real' metal and supposedly what isn't. Don't waste a lot of energy hating on bands you, or more so other people, don't like. You'll like some, you'll not like some, and you'll be indifferent to much.
As for me, I find that I like metal pretty well across the board with the one exception being that I need to believe that the band are actually musicians, with a certain level of ability, including decent vocals. I can't tell you how many songs I've listened to for the first time and, while listening to the intro, thought, "This has potential!" only to groan when the so-called singer comes in with the devil-dog, demon growl stuff. That really kills it for me.
Even so, I don't try to tell other people that it sucks or anything. It just isn't for me; I don't enjoy it. I think that's a good attitude. Besides, my own tastes have changed over the years, I may eventually fall in love with a band with just such a sound.
Ok, that's enough commentary. Back to the original question, here are a few more bands, that I didn't see recommended earlier (though I may have missed them in all the lists) that I'd recommend to you:
Overkill
Black Label Society
Godsmack
Mushroomhead
I did note that someone else mentioned Fates Warning already. I second that recommendation.
Enjoy!
