Indeed it looks like those three completely different design, although do seem to share the same font.
First, I would choose a theme (color scheme, font etc.) that fits the game: so if it is a Mario Kart like game, you'll would choose a cartoonish theme, if it is a space adventure you'll want to throw in a more futuristic design. Since a don't know what the game is about or what it looks like (besides the screenshot), it's hard to come up wit ideas of my own. However, you could look at some screenshot of similer, commercial games (
Google images!). That might give you some inspiration.
Second, if I would have to choose between the three different 'styles', I would pick the style as used for the inventory list.
The panel in the upper right corner looks very cool, but it might be difficult to maintain that 'look-and-feel' through the entire game, because of its complexity. But if you are (or know) a good designer, the may not be an issue.
The buttons in lower right corner could be an option, but I guess I would make them a little less transparant, to make them more readable. Also, you may use some more icons/symbols together with or instead of the text. As a player, it's easier and faster to recognize images, then to read text.
The lists on the left I like because of their simplicity. Again, icons could be used for user-friendliness and to spice up the looks a little.
I guess it's best to start make a list of everything that has to be displayed on the screen. After that, design a layout so everything fits and has a logical position. Then care about the actual design.