Piestewa is a nice little in-town hike. It isn't long but it has some serious elevation gain for those looking to get in a work out. Very popular (especially in the winter and on weekends) parking is the real limiter here. I hike at a brisk speed and have never had a serious problem with the trail being too crowded but the parking lot is just its own monster. I recommend getting in early or...well, I don't know a better option.
Still, if you have company in from out of town, it's a great 'things to do' (if you can get them out of bed early) with a [basically] all skill levels hike and quality 360 views of the valley.
There are some sister hikes to the main peak that, admittedly, I've never done. Just not really interested -- maybe one of these days.