Ok, i'll start thread with (computer) FPS maps, as it's what i played the most throughout my gaming path, but you can mention whatever you want, even tracks in racing games or stages in fightings.
Crossfire (Half-Life)
One of the truly immortal maps. Yes, the same one in which there is a bunker - you can lock yourself in it, leaving those who are outside to die from an airstrike (unless you do gaussjump high in the sky so you evade getting killed). And the structure is very good, with a multifloor building and various alternate passages - an experienced player can work out the ideal route options for himself during the match.
Undertow (Half-Life)
My second choice from HL1 will also be a gimmicky one. It has conveyor tracks, and a water canal connecting different parts of the map, and a empty water tank, into which you can climb into and settle in like a fort. And, of course, the hall, which can be flooded with water, previously locked with a grate so people under easy targets for fraggin and/or die from oxygene lack. For me, this map is of particular importance - it was with it that I began my acquaintance with the Half-Life series in general.
Avanti (Team Fortress Classic)
A nice Mediterranean town to conquer. By the way, it's partially based on the assets of the canceled first incarnation of TF2 - Brotherhood of Arms.
Well (Team Fortress Classic)
Map for capture the flag, among symmetric ones. There is also a tunnel in the central zone, which separates the two confronting bases, and various paths of passage, situated on different height (and depth - underwater swimming including) positions.
DM4: The Bad Place (Quake)
Meaty arena for smaller number of players. It is multi-floor, and there are also teleporters, so there are ways to move very quickly. The author of the map, our dear comrade American McGee, said that he liked how compact it turned out.
Q2DM1: The Edge (Quake II)
Another of the legendary maps, which is always held in high esteem by players: many servers constantly put it on rotation, epic duels of old-timers take place on it, and map makers make new remakes of it for this or that game.
DM-Gothic (Unreal Tournament)
For me, this one has always been one of my favorites. Luxurious gothic cathedral on a dark violet night. The map is quite spacious, it has many different walkways, balconies, openings. Always comes up when i remind myself on architecture in games. Of course, it's more fitting for higher number of players, otherwise you can get lost.
DM-Phobos (Unreal Tournament)
Luxurious space map. Verticality, as I like, is fully present. Also indescribable atmosphere.
DOM-Condemned (Unreal Tournament)
A small but very comfortable map from the "Domination" mode. Some kind of modern city, a completely dysfunctional area. Neon lights, graffiti on the shabby walls surrounding the skyscrapers. Cozy.
Q3DM9: Hero's Keep (Quake III)
Amusing map, many places where you can fall into the lava. Clear symmetrical structure, fun.
Q3DM13: Lost World (Quake III)
One of stable choices by competitive player scene among stock maps. Well, besides the balanced gameplay, I am also pleased with the organic theme present on the map here and there.
Q3TOURNEY5: Fatal Instinct (Quake III)
Yeah, that very foggy map on which the battle with Uriel takes place in sp. The fights on it can be pretty wild, with tricks and surprises.
SS7 -Original- (Daikatana)
Storm Sector 7. Strong deathmatch arena for a great chop party. It uses weapons from the first episode of game campaign, so it’s convenient to reach places that are inaccessible in the usual way with the help of a multi-barrel shotgun that has insane recoil.
Shallow Grave (Daikatana)
Great snow map. It is a medieval fortress. In the center of the tower, from it bridges lead to different parts of the castle, both in the interior and in other courtyards.
The Dojo (Daikatana)
I like to climb in the games on the ledges, on the roofs, climb high. So for me this one is very pleasant. Such a futuristic city with a multi-level area for movement.
AS-Convoy (Unreal Tournament 2004)
The map with the capture / protection of a moving train was already in UT99, but 2004 version is just even more epic.
ONS-Torlan (Unreal Tournament 2004)
The map, of course, is straightforward - but for me it’s very nostalgic, from the demo version of ut2k4. Back in days i was impressed - the hills, transport, using links etc.
CTF-MoonDragon (Unreal Tournament 2004)
Impressive map for Capture the Flag. Theme is an eastern monastery located in the mountains.
Overwatch (Half-Life 2: Deathmatch)
A map based on an episode in a game where he had to help Barney fight off snipers. Actually, the central high-rise building is quite a candidate to turn it into fort, while it's attackers make their way from the streets.
Resistance (Half-Life 2: Deathmatch)
Cool map, atmospheric and with a good layout. Interestingly, it turns out that this is a free remake of Bodies from the Blood multiplayer.
Venice (Cube 2: Sauerbraten)
Venice stays Venice. A city divided by numerous canals. Cube 2 has a lot of arenas, but I regularly return to this one. Although mostly I prefer just the instagib mode.
Thor (Cube 2: Sauerbraten)
Antique architecture, hidden under the arch of a huge cave, and water below. Classic.
Skycastle (Cube 2: Sauerbraten)
Although it was later removed from the official build, and a completely different author began to make the new version, I still gonna mention. One of the maps, that show quite a "freedom of creativity and scope." Since in Cube level creation takes place right in the game (built in level editor), you can do quite impressive things in simple ways (unlike quake or unreal where you need to be kinda a dev with 3d software and compile shit).
dod_avalanche (Day of Defeat: Source)
Well, of course, I could not ignore my favorite WW2 online mp game. I know that many people prefer DOD1, which is a mod for Half-Life 1, but I always played this one. Regardless, are common between both dods. An avalanche for dods is like crossfire for halflife or de_dust2 for counterstrike - one of the most beloved and sought after maps. And not without reason - it is always the guarantor of interesting battles, it has many different areas in which heated fights take place, and the advantage of one side over another can change suddenly. And how many memories of secretive passage through the house, while all the main forces are trying to conquer the fountain in front of the church ... Wow!
dod_colmar (Day of Defeat: Source)
On this winter map, not the seizure of positions, but the destruction of enemy equipment. The map is separated in two parts by a river with a bridge. There are also many potential points for snipers and machine gunners, but those positions are never too safe.
dod_flash (Day of Defeat: Source)
Easy-to-pickup and dynamic classic. A small village - the main vein of the map is a road that runs, meandering, from one end to the other. And on the sides here and there are alternative routes - through the houses, through the fields ... There is no position that requires as many as two players to immediately capture, so with enough agility and outsmarting opponents, sole soldier can turn the table around.
Furious Heights (Quake Live)
A well-proven arena, quite worthy of its reputation.
Ragnarok (Quake Live)
Beautiful map on the theme of fantasy Scandinavia. Here I like colors and layout.
Repent (Quake Live)
Absolutely medieval map. Also quite complex in structure, and very grandiose. Also there are very insanely hidden secrets in it.