Water Street is the party area of this fine city. You'll see giggling bachelorette parties, guys in suits, ladies dressed to kill, and scads of regular goofs such as myself. The area is a few blocks long and offers a variety of bars, pubs, and I believe there is a dance club, which goes against everything this area is about. You see, none of the places have dance floors. In that fine Milwaukee tradition, the bars have a party atmosphere rather than danceclub atmosphere. The music is usually played by the bartenders putting on cds, one song at a time, or playing party mixes. And they play a much better variety of music than any dance club you'll go to. Fr'instance, at McGillicuddy's you can hear hometown faves the Violent Femmes, Beastie Boys, Abba, cheesy disco songs, and a whole lot in between.
As far as the bars go, there are large multi-roomed places (McGillicuddy's, Mel's, O'Danny's), some smaller places (Rosie's, Oak Barrel) and even a dreaded sports bar. Whatever you're looking for, you should find it on Water St. (except for a dance club, but you can find those in a suburb nearest you).
Parking - you should forget finding something on the street and just park in the lot at the north end of the street. It might cost you $5 (oh my!)