Not having a lot of experience with microphones beyond those included in other equipment (such as those built into handheld recording devices), I was struggling to choose a good vocal mic. Based on recommendations from a singing friend (she's a singer - she didn't sing the advice) I started looking at the Shure range, and the SM58 in particular.
I didn't want to have to worry about phantom power, so the SM58 was a good choice, being a dynamic mic, and its cardioid directional pattern means it is less sensitive to background noise and feedback. Lots of singers choose these mics so who was I to argue. There are two versions - one has a switch to disable the mic - this is the one I went for.
When it arrived, it took less than a minute to hook it up to my amp and get it working - it sounds great and I'm very pleased with the purchase. Price was good, too!