With SteamPipe, you'll have to place all your custom content (UIs, crosshairs, sounds, scoreboard modifications, etc...) into the following folder:
C:/path-to/Steam/steamapps/common/Team Fortress 2/tf/custom
I'm using E.v.e HUD (https://code.google.com/p/eve-tf2hud/). It comes with a 32player scoreboard as well as a nice semi-minimalist HUD that you can customize even further. I also like the AutoUpdater program and it keeps the HUD always updated and installation is a breeze.
(http://sinders.comze.com/hud/normal_mode/payload.jpg)
Here are more screenshots. (https://code.google.com/p/eve-tf2hud/wiki/Screenshots)
What are you guys using for HUD?