It’s one of the most creative and liberating commercial outlet for artists and designers ( at least where the music industry and the artists themselves are mature enough to acknowledge that a poster is much more than a sticker with a date on it). As with any kind of illustration it shouldn’t be a literal depiction of the subject and it’s always more meaningful when the artist uses his own idiosyncrasies in envisioning the composition.
Here are some examples of posters I really liked, a few movie posters and concert posters tracked down from wellmedicated.com , all having a modern feel to them, with a post on older/vintage posters soon to come.
P.S. I may have chosen the posters for the bands I like.