I'm far from an expert on singing, but I want to pass something along that may be worth checking out.
For years I LOVED the bass sound produced by getting really close to the mic, along with the bass e.q. pushed up and the mids cut. Slowly I came to realize that a lot of this bass boost was totally wasted because I was boosting way below the range of the human voice. And by cutting the mids out, I was removing any shread of natural sound that was left.
What I was doing, and what I feel a lot of singers do, was introducing "mud" or an indistict boominess that made the words hard to hear and understand.
I no longer use the classic V e.q. on my voice, instead allowing it to be clear. I do use the proximity effect to add warmth to the sound, but now it no longer muffles everything.
The SM58 in particular has a built-in mid-range boost that really compliments a lot of male voices. The proximity effect enhances it. My point is just be sure it is enhancing, not muffling.
It has been my experience that many singers are like me--it took a long time to be able to tolerate the real sound of my own voice. Therefore I wanted to disguise it behind a lot of effects and e.q.
It finally sank in that it was counterproductive and that what I was hearing wasn't really the best treatment of the sound of my voice.
I now lean toward mics that have more of a level frequency response. Then when I work the e.q. a little it isn't overdone. I currently use a Senhnieser 855 most of the time. I have two of them.
I have an SM58, a SM87, a Samson Q7 (which, as Gary says, I believe is better for most voices that SM58), a couple of Samson R67s, along with a few assorted EVs and even some throw-away Behringers for guests to tear up.
In choosing a mic, it is essential to work with a few different kinds, adjust the e.q. and effects and try to record yourself. Then get some unbiased opinions about what sounds best for YOU.
Sorry for the rambling and I hope it didn't stray too far from the topic.
DonM