I just wanted to dedicate a thread to all the awesome developers out there that were lost or bought and dismantled.  My shout outs are...

Bullfrog Productions - I really wish there would be another Magic Carpet.  The game had strategy and action mixed to perfection.  I also enjoyed Theme Park and Syndicate.  I should have played Dungeon Keeper but I never did.  They were of course bought out by EA and then dismantled. 

Westwood Studios- I was a Westwood fan before eventually migrating towards Blizzard.  C&C was classic and it went toe to toe against whatever Blizzard could put out.  Red Alert was probably the peak of what they could accomplish.  Some of the best gaming memories I have were playing modem games against my friends with their first two titles.  Another developer that would be bought out by EA and dismantled.  C&C series never could compete against Blizzard after they were sold.

Criterion Games - Last swong song was a late NFS port on the Wii U.  This was actually the first EA game I've bought in over a decade.  Founders made a new studio and are working on a title with throw backs to Burnout.

Maxis - Had a blast back in the day with the with the first few SimCity.  I even bought SimFarm and thought about buying other Sim games.  They would eventually become another victim of EA.

Midway Games - Ms. Pac-Man, MK, NBA Jam, NFL Blitz...

Acclaim- MK, NBA Jam, Burnout...

3D Realms - Duke Nukem 3D and then Duke Nukem took Forever.  Played Duke Nukem 3D so much and always dreamed of playing it online through TEN (Total Entertainment Network) which I never did because it cost a monthly fee.  Had tons of fun playing it 1 on 1 modem with friends though.  I even designed a lot of levels myself and was so good at the editor that I memorized the numbers for a lot of the art associated with the game.  This would be the last game that I actually put effort into the level editor.  Perhaps Super Mario Maker will bring me back to my level designing days.

Dynamix - Made one of my favorite WW1 fighter games Red Baron (shows age way too much now but I loved it back in the day).  They also made Tribes which was way ahead of its time for an online FPS.  It allowed up to 20 or so people to play at the same time on a level.  This was back in the 56k modem days...  I was lucky to have an ISDN connection which allowed a sever advantage over almost everyone else rocking a 56k.  I believe this game is what led to the formation of Halo.  This game had bases, vechicles, option to choose light, medium and heavy armor, and many more innovations in the FPS industry.

I know there are plenty other studios which are defunct that deserve respect.  So please share your thoughts of lost studios that you wish were still around.  I'll add a poll eventually with more suggestions.

Rareware... Just kidding :P

Neverland: Developer of the "Rune Factory" franchise, one of my favorite game franchises ever. Rune Factory Frontier remains my favorite Wii-exclusive title, and Rune Factory 4 is my favorite 3DS title.

Acclaim: Developed and published several great racing games (mostly other genres, actually, but their racing games were what I knew them for best) during the 5th and 6th generations, including Burnout (1 and 2), Re-Volt, and my favorite non-sim racing game: Extreme-G 3.

Apogee! 

Ok, they are sort of still around as 3D relms, but I haven't seen things like:

Comander Keen, Monster Bash, Monuments of Mars or Duke Nukem (their version) in a long time.

Plus Remember LukasFilms Games -- anyone?

Loom! was a new fun and different kind of game.

Shit.. I'm getting Acclaim and Midway Games confused again...  Can you set me straight?  Both say they were developer and publishers.  I'm just confused on who did what.  Looking into it more Acclaim was responsible for NBA Jams...  Perhaps Midway published them sometimes on different platforms?  They had a close relationship is all I know.

Vigil Games: Developer of Darksiders I and II.

Irrational Games - this is the developer I'm truly respect because their Bioshock series, especially Bioshock Infinite - the one which hooked me into the series

Cing - another developer has my respected, Hotel Dusk: Room 215, LAST WINDOW: THE SECRET OF CAPE, ... these are the games you should play once time in your life

Hudson - I'm still loving Bomberman and Bloody Roar though 

And Another Code and Another Code R, Again (not classic Cing, but worth playing) and Glass Rose back on the PS2.

Came here to say Cing, really. Just yesterday I bought another copy of Last Window. A unique studio known mostly to Europeans that shouldn't have disappeared.

Irrational.
This was a big shame. Truly the biggest lost last gen. Absolutely destroyed me.

Ah, yes, Westwood was really great dev - Dune II pretty much defined what RTS would be, Eye of Beholder was on everyone's list if they were cRPG fans, C&C is still classic, and they made one of the most memorable P&C adventure games - Blade Runner.

SSI - one of those who are remembered by defining cRPG eras - their 'Gold Box' games from late 80's are still on every (serious) list - but it was with their war strategies that I spent more time than I care to admit - General (Panzer, Allied, Pacific...) and Steel Panthers series are still one of my favorites

TalonSoft - another turned-based wargame dev, their Battleground/Campaign series is always on my 'Top 10 IPs with more than 3 entries'

Delphine Software - one of my favorite devs on Amiga, with P&C adventures such as Future Wars and Operation Stealth, and classics Another World and Flashback

Cinemaware - another dev I loved in C64/Amiga days - Defender of the Crown, TV Sports games and one of my favorite Amiga games, It Came from the Desert

Interplay/Black Isle Studios - cRPG defining dev with Wasteland, Fallout 1/2, Planescape: Torment, Icewind Dale - luckily, their legacy lived on with Obsidian, Troika Games and inXile.