Ayecon is a new Cydia theme which is now available on Cydia for iPhone jailbreakers. The theme was made by Surenix, an iOS theme designer which already has some very popular Cydia themes.
Ayecon has been made specifically for the iPhone's retina display and the icons feature very high detailed graphics. It's a very colourful theme, using bright and vivid shades to really make those icons pop.
It's definitely isn't for everyone though and can look tacky at times.
I still find Jaku my favourite theme, it has a certain classy touch and doesn't use iOS' hideous shiny and glossy touches.
You can find Ayecon on Cydia for $2.99.