Sadly, I'm not currently running a Shadowrun game atm, but this question spans all modern-early future game.

Scenario-a villain is using a basic warehouse with some modest (modern era) electronic security and guards.
Problem is this-How do I make this feel iconic?

I feel that combat that have different levels of terrain(allowing free running) cover (because no one wants to eat a bullet) areas for stealth, etc make a place feel like a memorable fight. After all, you remember that fight on the speeding train where you had to dive off a bridge, you may not remember the fight in the blind alley.

So, as cross-system GM's, how do you make your combat areas feel like something special?

*Edit: Also, I do know how to spell terrain correctly, just not at the moment it seems.

Give them reason to exploit the terrain or atleast explore it.
Maybe there's an object they need to interact with.
It might be something as simple as a killswitch in an akward spot (at the end of an elevated walkway for example) or maybe it's moving making them inclined to move about (Like a suitcase with important macguffins being passed between the goons)
Give them something that makes the scene feel interactive, like a storage unit they can drop on the goons... or a forklift, because running people over with a forklift seems awesome.
Give them something that makes the scene stand out, like goons assailing them from the top of a stack of crates or a thrump card hidden in a storage container.
Have interesting obstructions and doodads, maube there's an oil spill they can slip on (or ignite) Maybe the quickest way between two walk ways is jumping on the container suspended in mid air, maybe shooting at the big gas tanks is a really bad idea.

The hardest part about all of that is making sure it's not nullified by "I shoot him with my gun"

I try to make my terrain make sense and feel natural - so no FPS corridors and the like.

If my runners are (for whatever reason) in a laundromat, for example, it's gonna be accurate to life. There'd be a big front room with all the washing machines and driers, and in the back there'd be a hallway with some small cramped rooms leading off it, including a business office, a small storage room, and a bathroom. A hallway isn't a great place to have a fight, but since it's close quarters and there are numerous doors, each doorway can serve as a source of cover. Bathrooms are pretty sparse for protection, but if the door opens inwards it gives at least some concealment and cover if needed. The storeroom is a little larger and has shelves to hide behind, but also has no windows and will be very dark if the lights are off. And the business office may be relatively empty, but if it has a side window opening onto an alleyway you never know who or what might come in or go out through it.

I find believability and interesting combat makes a scene much more memorable than anything else. If they can picture the place they're fighting in, and if the impact the terrain has on their fight is noticeable, they'll talk for a year and a day about "The Laundromat Incident", even if it was just a routine fistfight against some chump gangers. "Remember how Stacks just grappled the punk and threw him out the window? And then a minute later when he literally tore the sink out of the bathroom wall and threw it at the guy in the front room?"

If you really want advice? I say go watch a bunch of classic Jackie Chan movies. The car factory finale of Twin Dragons. The boat scene of Dragons Forever. The Pachinko Parlour in Thunderbolt. The bar fight in Rumble In The Bronx. The rooftop showdown in Who Am I?. The steel mill fight in Drunken Master 2. Mundane places that become instantly memorable thanks to clever usage of the environment. If your players don't take advantage of the terrain, you can and should have the enemies do so.

~Umi

I like to describe the reaction to every action with a little flavour. If a player one shots a guy and my description is "he's dead. Next?", the game gets pretty stale. I've had good results describing it as either something gross like "The bullet catches him in the throat, his eyes go wide as the blood wells from his mouth and over through the fingertips desperately clutching at the hole in his neck", or "The manabolt cuts him down like a doll without a string, and you hear the wet crunch as his skull connects with the pavement". You've got to give players stimulating material to role-play with.

In the case of the environment, think about what the environment is used for and what materials are present. In the case of a warehouse, what is in stored there? How is it stored? Piled in the open? Cardboard boxes? Wood? Shipping containers? How is the cargo moved? Overhead crane or pulleys? Describe the chains and hooks. Forklift? tire marks and oil slicks on the concrete. What are the lighting conditions? Is it day or night? Are their skylights? Light filtering through the bullet holes in the walls?

Now what happens to the environment in a firefight? Hit a pile of cocaine with a bullet and you've got white clouds puffing into the air. Wood turns to splinters. Metals will spark and dent or be punched through. (Unless you're playing total film, maximum explosion style) a petrol tank or barrel that takes a bullet will start spilling over the ground. If it is wet, the shell casings will sizzle and create steam as they hit the puddles. Does that guy who was shot while running to cover land in a pile of empty cardboard boxes and disappear? Does he hit a shipping container with a reverberating "gong!"? Don't be afraid of onomatopoeia used sparingly.

Imagine, would the Matrix lobby scene have as much impact without the collapsing marble walls? Would the stripper's death in Blade Runner stick in your mind if she didn't crash through multiple sheets of plate glass, with blood welling in her transparent raincoat?

It's interesting to me how all the responses given shows a really different approach to GMing.

I'd agree with all of the above, and maybe throw in little add-ons that the players could use to create cool effects during the fight (and be rewarded for). I remember reading one of the adventures in Elven Blood where (without going into spoilers) at one point there was a barrel of diesel fuel in a wooden building, and a cute little note in the background text offering stats for burning diesel fuel "just in case" they were applicable. If you're the kind of person that plays RP-style video games and gets into the habit of clicking on every obect in the room to see if one of them does something cool, it's sort of the same feeling.

Also remember that there's parts of the RAW that let you give extra Karma out for "smarts". If you want, you can give the players a carrot by making it clear that someone got an extra Karma point for their use of the terrain/environment.