OK, if it helps any, I went from an E270 S211 Avantgarde with virtually nothing to an E500 S211 with just about everything. Here's what I've found.
COMAND. Necessity. Couldn't live without it.
Luxury Climate. Nice. The extra rear vents are a real bonus with rear seat passengers and evening out the temperatures.
Sliding boot floor. Yep, great for sitting on whilst having a brew. Breaks up long journeys nicely. I keep a flask - hate motorway service prices.
Electric tailgate. Yep, no more mucky hands from closing a less than clean tailgate. Works like a champ, even with a well loaded boot.
Airmatic. Wouldn't have it any other way. Much smoother than standard self levelling. The lift is also handy for grassy lanes (I shoot and have dogs)
Memory seats. Set it once and forget it forever. Fantastic. Also like the easy in/out features of it including leccy steering column.
Parktronic. The ultimate aid to preventing parking dents/scrapes. I have it front and back.
Nappa leather. Much nicer than standard mercedes rhino hide
Distronic. Much better than speedtronic. Can be used safely on busy motorways. But, doesn't work in heavy rain or spray. Also makes the grille a bit messy IMO.
6CD in dash. Saves digging around in the boot. Better than a cubby hole which never gets used.
Keyless go. Love it!! Would always have this option if ordering from new.
Electric sunroof (rare). Nice if you like the extra light. Great to help keep the car cool when parked up - heat rises out of the tilted roof.
Logic 7 harmon Kardon sound. Yeah, if you like music nice and loud. Lose a bit of storage in the boot due to the subwoofer.
Heated front seats. Always make me feel like I've wet myself. Would rather have a cold ar5e personally.
Fire extinguisher. Like I'm ever going to use it. That's the job of the Fire Brigade who are much braver than me.
Wood/Leather steering wheel. Nice but not quite 300 quid nice.
Linguatronic - not got it
The tight git who ordered my car new obviously couldn't afford it
Anyone know what other options I'm missing please?