You have an X5, right? So you're QVGA. Cool.
That means you can use lots and lots of skins; you're spoilt for choice. :approve:
There's plenty of extra skins you can try at this site:
http://home.planet.nl/~verho612/Gssite/gsplay.htm
Pick one you like the look of, click the Download link for it, and save the ZIP file. Unzip it to somewhere temporary, and you should have a new folder with all the skin graphics inside, as well as a
.GPS file.
Copy this folder to your Axim - anywhere will do, I prefer to keep all the skin folders inside my GSPlayer folder which is on my Built-in Storage.
Then open GSPlayer, go into the Tool menu, tap Options, move along to the Skin tab, then press Browse.
From the file browser, find where you put your skin folder, and choose the .GPS file. Once you've done that, Ok out of GSPlayer's options, and you should see your new skin.
As for the equalizer, it comes built in to GSPlayer. From the main playing screen, go into the Tool menu, then choose Effects at the top. You should see the Equalizer, and you can tweak that there. You can also play with the other effects on the other tabs.
Hope that helps. :approve: