I guess I can give a serious response.
I like having a variable zoom scope for spotting on all my guns. Most sights aren't that effective for aiming at airsoft ranges... although occasionally it's nice. So I prefer to be able to take a look around at higher magnification. EOTechs and the like are very aesthetically pleasing on guns... and honestly, that's enough of a reason for me to carry around an extra pound of weight if I don't feel the need for a scope. Airsoft gear for most people is about looks more than function though.
If you find yourself resting the front of your gun on your fist, pointed vertical, a lot... then a vertical foregrip is for you.
If you find yourself wishing the front end of your gun hand a nice 25-30 degree angle grip on it, then an angled foregrip is for you.
If you prefer to hold your gun from the magwell, a magwell grip can make this much much more comfortable.
Slings are great if you ever find yourself climbing, walking long distances, carrying objective items or switching to a secondary on a regular basis. For smaller guns, I prefer 1-point slings slung to drop the weapon to the off-shooting side, leaving the dominant hand open for whatever use you see fit. A 3-point is a great all-purpose sling, can drop to off-hand, carry cross-chest or sling it behind you.
Bipods are nice if you spend a lot of time prone and pointed in one direction.
Lasers and lights are almost useless in all situations except at night games.
G Launchers are heavy and of limited utility... but when you need one and have it, it makes it all worth it. But a hand-thrown grenade is almost always just as good.
Bayonet is stupid, dangerous and irresponsible. Don't do it.
As for aesthetics, I would say change the paint scheme (I hate OD+black) and swap the stock for either a full stock (great for holding gigantic batteries) or a MOE stock... they're very pretty. A full stock might look kinda weird on the gun though.
Comfortable pistol grip is important for long games... or at least a "gapper" for regular style M4 grips are a necessity, especially if you don't use gloves while playing (which I HIGHLY recommend, by the way).
