Thank you to everyone that entered! It was difficult choosing five winners from the many entries we had.
All of the winners below met the requirements I specified in the first post. I've also tested each background for quality purposes.
1st place - @RobFerrari - 5000 xats
The neon lights offer a stylish nightclub ambience to the chat without being hurtful to eyes. The magnet has clever symbolism - we aim to collect/attract feedback to the chat. The second entry also has colourful speech bubbles in different languages, which reflects the international status of the chat. Both entries are worthy winners in their own right, but I'm including them both together because they're similar themes.
2nd place - @iSanty - 4000 xats
A simple but very professional design. These could be the graphics of a large corporation - they have that high quality look to them. There's also a cartoon vibe that suits xat in general.
3rd place - @Steven - 3000 xats
A clever design that integrates the name of the chat to help represent its theme (letting your voice be heard). The red rings add layers of depth to the inner background, and they also represent sound pulses.
4th place - @Ethan - 2000 xats
These designs look great visually. The first entry has a sad nighttime atmosphere, and the second has a retro arcade game vibe. The second could be perfect during spacewar contests. I'm grouping these backgrounds together as they're both dark and purple/red, and I couldn't decide between them.
5th place - @REDDS - 1000 xats
Another set of designs that are visually awesome to look at. The space theme suits xat in general, and the improvised Feedback logo is clever with the arrows, which symbolises how we receive feedback and then feed that into other systems to help improve them. However, the UFO isn't very crisp on the outer chat preview and the banner is directly cropped from the outer background, which prevents it from ranking higher.
Please find me at Feedback chat to collect your prize, or if you send me a PC on the chat, I can come to you!