Hmm... this could be a tricky one. Number 1 is definitely the easiest.

1. Atlus
2. Squaresoft (pre-CD)
3. Nintendo
4. Enix (pre-merger)
5. Intelligent Systems

1-Ensemble Studios
2-Blizzard
3-Lionhead
4-Sony Santa Monica
5-Capcom

1- Bethesda (hope elder scrolls V comes out soon, Fallout 3 was good too)
2- Nintendo (mario and zelda)
3- Blizzard (Diablo II)
4- Capcom (RE)
5- id (wolfenstein, doom and quake)

Is this publishers or developers?

Nintendo EAD Tokyo (Mario, Donkey Kong: Jungle Beat)
Game Freak (Pokemon, Pulseman, Drill Dozer)
Intelligent Systems (Fire Emblem, Advance Wars)
Hal Lab. (Kirby)
RARE pre-MS (Donkey Kong Country, Banjo Kazooie, Goldeneye)

ok other than Nintendo and its (ex) second parties.

-Blizzard (Starcraft)
-Konami (Castlevania, Gradius, and Contra teams)
-Capcom (Megaman)
-SEGA (Most Sonics before Heroes, Streets of Rage, Virtual Cop, House of the Dead, Madworld)
-RARE (Post MS, Kameo namely)

Nice list.

@post above: I strictly meant developers, not publishers.

I'm sorry to say I haven't really heard of Atlus. Is anyone willing to summarize the case for them?

1. Nintendo
2. Capcom
3. Rareware (in 90's)
4. Konami
5. Sega

Shin Megami Tensei/Persona. One of the best RPG franchises in existance and definitely the best in the last years. That was easy

5: Westwood. Why? Because they invented my favourite genre (RTS) nuff said

4: Sega. Why? They are very hit and miss, but when they get it right, they really get it right (phantasy star 1, 2, 4, and online, Sonic in 2D, etc.)

3: Valve. Why? CS is the third best E-sport game ever. Half life is almost single handedly keeping the FPS genre interesting with the innovations the series brought. Also, they always puts gameplay first.

2: Nintendo. Why? Because they're F*king Nintnedo, their games are in an entierly different legue compared to other game companies. Their games are different mostly because of their richness of ideas and how these ideas are almost always flawlessly implemented. There is a reason as to why Nintendo games sell so many copies.

1: Blizzard Entertainement. Why? I have plenty of reasons to put Blizzard in number one, but the main reason is that they made Starcraft. The best E-sport game ever, and Warcraft 3, the second best E-sport game (They also made the Diablo series). Blizzard always takes their time with their games in order to tweak them to perfection, and even if a game turns out to not be perfect after release, they patch and support it for over a decade (Starcraft is still being supported after all these years). Blizzard has proven themselves to always put the consoumer first (I just hope they doesn't let themselves get influenced by Activision)

1. Rockstar North
2. Infinity Ward/2015
3. Valve
4. Bungie
5. Bioware

Sry but I just have to name these great studios as well:

Ensemble Studios
Naughty Dog
id
Epic Games
Bethesda
Insomniac

1. Infinity Ward
2. Nc Soft
3. Square Enix
4. Rockstar North
5. Epic