I know this thread is pretty old by now, but here are some neat tools I use in my stream. You probably shouldn't use all of them for the sake of simplicity, but you might want to use a couple.
Button input overlays: http://skullgirls.com/forums/index....ers-how-to-display-your-inputs-on-stream.396/
I personally use ApVkp with ZeKnife's beautiful button images because it works with keyboard, but there's a lot of stuff for stick/hitbox users too. Just be sure not to make your button inputs too big or too small. You want people to see what buttons you're pressing, but you want them to see what your button presses are actually affecting in-game, too.
Screen overlays: http://skullgirls.com/forums/index.php?threads/stream-overlays-share-your-screen-obscurers.6536/
Just to note, the screen overlay thread is less about giving away overlays and more about showing them off. You should use the overlays there as a source of inspiration, or if you're really desperate, you could ask someone there for permission to use one of their overlays in your stream.
Winamp AVS (Advanced Visualization Studio; programmable real-time visualizer): http://www.winamp.com/ (Info) | http://forums.winamp.com/showthread.php?t=374929 (Downloads) | http://forums.winamp.com/showthread.php?t=209060 (AVS tutorials (if you want to make your own presets))
I use v5.5. People tend to have problems with AVS on the newer Winamp versions, so you may want to try an older version if you're having trouble. Note that Winamp is fairly old by now and it has some strange problems on Windows 7 and up. The only problem that's ever affected me has been crashing during song transitions while editing AVS variables.
If you need some cool visualizer presets (not satisfied with available visualizers/don't want to make your own), I'd be happy to share a few that I've made.
Be warned that AVS uses a single core and doesn't use your graphics card. Some presets can lag pretty badly if all of your cores are already in use, or if your individual cores aren't very fast (AMD). You'll also need to increase your bitrate quite drastically if you want to maintain quality on your stream, though you shouldn't need anything higher than 5000, and it should already be pretty high-quality anyway if you're streaming Skullgirls.
If you want to know what AVS looks like, here's a sample video. AVS will stretch things, but it won't distort them unless you're using images or other aspect ratio/size dependent things. You can make it short, long, tall, wide, thin, whatever you like.
Oh, and if you want, you could try VSXu Artiste in place of AVS, but it's a bit more intense and might not be what you're looking for if you just want to quickly set up a basic visualizer. VSXu also captures all system sound, so it'll visualize sound effects coming from Skullgirls. That may or may not be what you want, but if you're not playing any music, you could make a weird visualizer based entirely upon in-game sounds. I don't know. It's up to you, really. Go wild.