Here's my thoughts and not in order:
- gaptech remote roof / one touch (couldn't be without)
- LeatherZ Door Armrests (well, I use everyday but not a must

)
- remoted engine heater (Webasto. Very nice to have in winter)
- hard top (as above, very nice to have especially in winter)
- automatic transmission (manual is not for me)
- cruise control (I use it A LOT)
- MFSW / M wheel (so nice)
- wind deflector (sure)
- warning triangle (never used and hope I don't have to. It's good to have though. Same as the first aid kit)
- electric heated sport seats with memory (I have key memory, so Ms. Dice uses her own key.
1=Dice, 2=Ms. Dice 3=Get ready... vacuuming position (goes all the way front).
- isofix (useful? Not yet but good to have)
- xenons (very happy to have)
- 3 flash turn signal (very useful mod)
- ac (sure, don't they all have it?)
- radio, cd, aux-in (very important)
- auto lights (I have but always do it manually)
- alloys style 135M winter, style 224 summer (I love them both!)
- sat nav (doing a retrofit someday...)
- pdc (yes, maybe in front someday)
So in real life, what do we really need and what is just good to have, that is the question. No answer, sorry

.
Cheers
Dice