Let's discuss user interfaces

In the open Sunday thread several readers suggested I start a thread about graphical user interfaces (GUI), and how important they are for games, so here it is. The GUI is what connects us to our games, which is why it is very important to be done right. But there are a lot of pitfalls how it could go wrong.

One major problem is information overload. Too much information displayed, and you end up not noticing any of it, because even important displays get burried in a mountain of data. Especially single-player games nowadays have a strong tendency to minimize user interfaces, for example displaying your health by the image becoming red instead of having a health bar you might overlook. While I haven't played it, I saw videos of the new Splinter Cell: Conviction, where even the mission goals are projected onto the walls instead of being shown in a window, way cool!

One technical difficulty for graphical user interfaces is scaling. You can play games in lots of different resolutions, with screen widths ranging from 800 pixels to 5700 pixels. But user interfaces in many cases don't scale very well, because they use a fixed number of pixels, not a fixed percentage of the screen width. Thus if for example a game is using a 10 point font, that looks large on a 800 pixel wide screen, but tiny on a 24" 1900 pixel wide screen. In the early days of World of Warcraft I played on a 17" screen with 4:3 aspect ratio, and the various UI addons for raid healers took so much space, that I only ever saw Molten Core through a small window in the middle. My current 22" wide screen is a lot better there.

The biggest impact on the user interface of a MMORPG is the developers decision on how much modification to allow by the users. The user interface of World of Warcraft improved a lot over the years, because Blizzard not only allowed addons, but then also integrated the functionality of the most popular addons in the standard user interface. Can you believe that when WoW came out, there was only one single hotkey button bar, with no possibility to show more than 12 buttons at a time? It's true, and addons changed that.

The downside of user-created GUI addons is that they have an impact on the difficulty of the game. For example I have Deadly Boss Mods running, and whenever a dungeon or raid boss targets me with an ability from which I am supposed to run away, the "run away little girl" from the Big Bad Wolf event in the Karazhan opera plays, making it harder for me to fail to notice what I should do. One extreme example was recently shown on MMO Champion, where the Augmented Virtual Reality AVR addon makes it possible for a raid leader to mark the ground with circles and symbols as in "healers stand in the blue circle, ranged dps in the green one, and when boss ability X triggers, run in the direction of the big red arrow!".

So, tell me about your experiences with user interfaces in various games! What game has an exceptionally good GUI, which one an exceptionally bad one? How important are GUI addons for you? Discuss!