18" wheels & Xenons are a must have!
Winter pack is a good choice too, but not a must have I suppose.
DSG - I hated it, but that's just me.
Cruise control is a waste of money - every car I've had it on has seen it hardly ever used
I've found the park sensors really worth having and yes, the seats are the same design, leather or cloth. Personally, I hated the cheap looking check cloth and went for leather - so much nicer and easier to maintain - plus, yes, it does help at resale.
The options I have on my gti (took deliverey last week!) are
3 door manual, tornado red... 18" wheels, leather, sat nav, uprated speakers in front, armrest, cd changer, winter pack, park sensor, electric folding mirrors, hi line computer, boot liner - plus, R32 rear lights & colour coded rear valance/skirts. Once it's run-in... oettinger exhaust with Morego remap to 250bhp & handling pack