As you know, I keep my eyes open for unusual or striking themes, in this case falling in love with this night sky-themed design from theme-maker favourite MMMOOO, but in particular for some of my older (pre-Belle) smartphones. Star Trails is free and does work on all versions of Symbian, but in my eyes it's optimised for S60 5th Edition/Anna and even older QVGA devices, as snapped below. 

Here are some screens of Star Trails on the Nokia X6, running S60 5th Edition*:

* in case you were wondering why the UI looks a little 'different'...

You can download Star Trails for free here in the Nokia Store. Note that it's almost 2MB, so there will a slight performance penalty, especially on the older phones. Still, worth it for a little style, eh?...

Here's the theme installed on the venerable QVGA-screened E72. Looks good, doesn't it? The circular highlights around the app icons get a little pixellated, but overall one of my favourite themes for older S60 3rd Edition devices: