Ok, Im in fully serious mode for this post only.

Do all the mercedes recommended service. When parts break, ask to see the old ones and inspect them. Have the mechanic show you what failed.

Do not overheat the engine. If the engine is going to 110 degrees C or hotter, pull over and let it cool down. It should run somewhere between 80 to 100 degrees C. Even on the hottest day, not over 100. My car runs 100 degrees C in 120 degree F weather.

Change the oil at the scheduled intervals, change the brake fluid once every two years I say especially if you are easy on the brakes like you said. I usually change mine once a year because thats just how it works out. For instance, last year, I decided my brakes were mushy, so I put on a new master cylinder, and then brake lines, then before that, one of my calipers was leaking, so I flushed it each time (brake fluid).

You should floor your car every once in a while.

(sorry I cant be this serious, just not part of me)
Think about your own body. Do you ever run at a sprint or top speed? I do at least once a week myself. You know, dont you chase your brothers and sisters around the house at a full sprint. I sure do.

(serious again)

You should read the thread on the E55 break in procedure.

Break-In period

one of the replys says to floor the car...etc.

__________________
Current Stable:
1994 S500 v140, 210k miles, white with grey.

Former Mercedes in the Stable:
1983 300CD Turbo diesel 515k mi sold (rumor has it, that it has 750k miles on it now)
1984 300CD Turbo Diesel 150 k mi sold
1982 300D Turbo Diesel 225 sold
1987 300D Turbo Diesel 255k mi sold
1988 300 CE AMG Hammer 15k mi sold
1986 "300E" Amg Hammer 88k mi sold (it was really a 200, not even an E (124.020)
1992 500E 156k mi sold
etc.