Well, I would say if you want that first meal to be a memorable one, find out (if you can without him knowing) what his favorite meal is. If you are unsure how to make it, just google it online and get the basic idea. Also a candlelit meal would surely add extra points, as well as a good dessert. Have fun, enjoy and I hope your evening is already off to a good start. By doing these things, it's sure to be a hit. One he wont soon forget, and lets face it, that's really what its all about.
For my future husband's first home-cooked meal, I made lasagna, fried chicken, and dessert. I don't remember what else I served. Later found out he does not like eating chicken off the bones...oops. The lasagna was a hit. I'd recommend lasagna instead of spaghetti because it is much easier to eat in a neat manner.