Xenon headlightsAn excellent choice if you do much night driving.
Electrically foldable door mirrorsAll depends if you need to fold your mirrors regularly. I didn't go for them.
18 inch monza'sThey do look good when compared to 17's. But I prefer a thicker layer of rubber between me and the road.
Parking SensorThe golf is not a difficult car to park, visibility is good, when compared to say an A3. (But if reverse parking is your Achilles heel...... )
centre armrestCockpit looks a bit sparse without it. A definite choice. (just noticed that this forum would not allow me to type cock, ooh, er, missus

. It's Carry On weekend on UK Gold by the way

)
Winter packYou may get a bit of this if you choose xenons. But heated seats are only necessary with leather.
Metallic PaintIf your choosing Black then it
must be Metallic
Another option you haven't mentioned, though it is a dealer fitted job, is the iPod adapter. A definite choice if you are an iPod user. looking at £150 ish.