1. Nintendo EAD
2. Valve Corperation
3. Squaresoft
4. Rockstar North
5. LucasArts

Some honorable mentions include Brøderbund, Cyan Worlds and Interplay Entertainment among many others I'm too lazy to post right now.

 Mine is. 5)Atari. 4)Sega. 3)Sonic Team. 2)Nintendo. 1)Rare. And if only Microsoft didn't buy Rare.

My favorites in no particular order 1) Gearbox 2) Square Enix 3)Sega 4)Valve 5)Nintendo

1. Valve
2. Square
3. Nintendo
4. Atlus
5. Konami/Kojima Productions

All in no particular order, other than number 1.

My top 5 are:

1.) Take-Two Interactive (2K/Rockstar)
2.) Nintendo
3.) Sega
4.) Atari
5.) Ubisoft

99tables : Yeah, it doesn't make sense that Microsoft bough Rare, if it was Nintendo that bough Rare, that would make perfect sense.

I've never put much thought into it, but it shouldn't be too hard.

1) SEGA
2) Gearbox Software
3) ZUN/Team Shanghai Alice
4) Nintendo
5) Pixel

Since I chose a couple of obscure devs, here's the info for Pixel and Team Shanghai Alice. Gearbox shouldn't be TOO obscure, but they did Borderlands.

I would have MAYBE included Capcom, but because of their money-grabbing techniques, ruining Dante's image, and trashing MegaMan (Granted it was because the owner of MegaMan left them), they pretty much lost most respect from me.

Mine would be:

1) Level-5
2) Square (...Enix, I suppose. *SIGH*)
3) Bullfrog (console games, but awesome)
4) Bioware
5) 2K (whoever they are now-Irrational games?)

None of them.
When one gets good? Something always happens to muck everything up.

T.H.Q. "went under" and my favourite Zelda Replacement series is canned. ("Darksiders".)

Capcom Wants new audiences and Craps all over Devil May Cry, and MegaMan. Then Changes the Strategy Element to Marvel Vs Capcom by jamming the punch and kick buttons together. And saving other elements for "D.L.C." and over producing extra versions of the the same game that still need "D.L.C." from the previous instalment???

Namco decides to release an incomplete Soul Calibur 5. (Still playable. But incomplete.)

Square has not made anything I am interested in for years. (I think The Final Fantasy 7 Prequels and the "Dissidia" Games were it.
BUT
They were released exclusively for particular devices. One of the reasons I stopped buying Squares Stuff. I should not need a PSP handheld, A standard at home Playstation console, And a Cell Phone to get my Final Fantasy Fix. We are talking about al least $1,000.00 U.S. Bucks for the gear before a single Game is even considered to be Purchased. (That is if you want the full "Final Fantasy Experience".)
PLUS
They keep changing the combat system to some miserable experience that tortures the mind to the point of insanity. With Each New Game Since The 8th game? (Not saying "Dissidia" was a bad Idea. That Needed to happen. Just pointing out this new stuff for the R.P.G.'s would be allot more fun if I did not have to "Reinvent the Wheel" every time I wanted a new story to play and read.)
"AND THEN"....
Voice Actors?
For many games I think they can be taken out of the experience. Particularly for many R.P.G. games. I am not a fan of gratuitous spending when it is not needed. If people think that the action would be interrupted? It does not have to be. Just provide subtitles and enjoy the show.

Lucas Arts Gets it's staff laid off and the property sold to others. (Bye bye Force Unleashed. My Favourite Strider Replacement. Replacement due to lack of a sequel for the modern generation.) (Bye Bye X-Wing, and Tie Fighter. My Star Fox Replacements.)

"Rare" Get's all of its Ideas cancelled and shelved for the "Gimmicky" and "Kiddy" games that they really do no want to just solely do. (Bye bye "Killer Instinct". Bye bye "Conkers bad fur day". They are Just good games.)

Either Greed Gets In the way of genius. Or Big Companies Wanting to crush the competition (for Monopoly reasons) by throwing Big Money and Big Adds instead of Innovations at the development of a game halts or hinders the worlds of brilliance and entertainment that could be had.

They also shorten the length of many to unneeded proportions to get the next wad of cash out of the same consumer. Or they make you pay extra for the D.L.C. witch is 1/2 of the game in some cases.

I have never needed D.L.C. and I will not bother with such stuff. (They get enough for that Disk that only cost them pocket change to make. I do not want to hear any "Nay sayers either. If the disk form did not save them cash they would have stuck to cartridge form. Plus if the Game is too big for one disk? What is Stopping them from using multiple Disks Like Final Fantasy 7 or 8?)

I have had it up to here with many of the practices of the modern games business practices.
I rarely buy a game brand new. The last one I got new was "Devil May Cry H.D. Set." Three games in one disk and no "D.L.C." needed either. About 100 hours of entertainment if one is inclined. About 20 to 30 hours bare minimum for one of the 3 games. Plus Extras.

Ultimately I am unimpressed with many of the companies that are left still standing during this economic recession.

The only one I LIKE so far is "Konami". (At least you know you get your moneys worth. Even if the last "M.G.S. Rising/ Revengence" was only a few hours on the short side.)

Good Luck.

Good Luck To All.
I'm done. Stick a fork in me.
Peace.

My Favorites are

1) Nintendo
2) Square Enix
3) Ubisoft
4) Konami Digital Entertainment
5) CAPCOM

5. Square Enix
4. Gearbox
3. Nintendo
2. Ubisoft
1. Bethesda 

My top five game developers are:
1.) Rocksteady- with there current installments in the Batman franchise they earned this spot on my list and because they made one of the best to date street racing game, Midnightclub LA, also they made games like GTA 4(Grand Theft Auto 4).

2.) Epic games/Ubisoft- Made the Gears of war series, as well as the Halo series, which are some of my favorite games to play.

3.)Capcom- Although they have stopped making Megaman games, I was a fan of the Megaman Zero series, and the Megaman ZX series.

4.)Nintendo-Well ( I know what some people are thinking, #4 on his list this guy is crazy) Nintendo has made alot of good quality and enjoyable games like Mario Kart, Super Mario World, New Super Mario Bros and so one but the series does get repetitive and a little boring after a while and seems to give me the feel like I've played this before.

5.) Gamefreak- Well all these guys is known by me for is Pokémon which is extremely repetitive in its story lines/plots, and only seems to add one or two new features as games come out for the franchise. I am excited for there newest Pokémon game to come out, X and Y mainly because I've been a fan of Pokémon since I played Yellow at the age of 6 and because of its all new features and  its in 3-D and looks very promising. 

f*** thats hard

My top 5 favorite game developers would have to be: Square/SquareSoft/SquareEnix, Arc Systems Works, Aksys Games, Ubisoft and Capcom.

mine is

SquareEnix

sega gen

capcom

nintendo

Gamefreak

1. Rockstar North
2. Naughty Dog
3. DICE
4. Ubisoft
5. Double Fine