You know what REALLY old games I enjoyed?
SSI's Cosmic Balance I and II.
In the first one, you designed a spaceship to do phased-turn combat with. You'd enter in your commands for the next 30 seconds, and your opponent would do the same (hotseat) then hit "start". I always wished that there had been a recorder, so that after the battle you could have seen the whole thing from start to finish.
The second one was a 4X type game, and you used the ships you designed to fight the battles that occurred on the strategic level. You had to built commerce grid between planets to generate resources to build your ships. You could make ships that had double-sized jump drives that could go into enemy sectors and "commerce raid" then get back into friendly territory before the turn ended (any ship that ended a strategic turn in enemy territory was lost.)

GOG is already using DOSbox for the DOS games. As for older games, sure, why the hell not? As long as they're good games, anyway. I don't suppose graphics would be off-putting to people, though the difficulty levels and complexity of some older games might be. It's a niche within a niche that's worth exploring, at the very least.

Thats thru and so not true at the same time. :) I can remember those games that was so hard that you had to be a superman (or this guy) just get on the last level. Then again there were games that was just too easy... (Larry 1... ) and not enough playtime for your money.
However GOG is not the only one who is making old games to work with new machines. Steam has been mentioned so many times over that I am starting to think that they are trolling this forum :-D but then there is Sierra who released Space Quest and Police Quest collections on DVD (all works with Vista) and some older games ... well.. They are just free now... (GTA1, Fredrik Pohl's Gateway , etc...)
So my point is... *looking for it* ... Well ... My point is lost, but anyway... I dont think that it is worth it...

I went and looked at Steam, and honestly, I am not impressed with their game lineup. The only games there that interested me were X-com, and Worldwide Soccer Manager 2008, and WSM I'll get direct from their website rather than through Steam. (I still hold out hope they'll make another Hockey manager game)
I think GOG is going in a direction I like to see. I'd still like to see more developers and more older games, but I am sure that is coming.

I've wondered about this too, as there are some old SSI & Microprose games I'd love to see. The main issue I can think of though is getting past some of the copy protection schemes these games have. Most of them had you reference the manual to identify certain things, like randomly asking for the fourth word in the third paragraph, or having you use something as arcane as a code-wheel, just to start the game.
I swear, some of the old DRM was almost as bad as the current batch! I suppose there are ways around it, but without modifying the code of the original software, it'd involve printing out pages upon pages of manuals.

Getting past of the copy protection is the easy part - Gog or anyone else cannot publish game without the permission of copyright owner and I haven't seen any CD remake of old game which actually has copy protection still in use... I mean that they will be removed for this purpose.

Depends on the rights. That's the only hurdle they really have to worry about, since the compatibility side of things is a dead issue thanks to dosbox.

How about really really old games?
In fact how about bundling A few games together in one download, I was A speccy user and seeing A collection of Ultimate play the game(tm) games or all the magic knight games put together in one package would be irresistable to me.

It would be nice to have a "best of" collection from the days of yore...
Say a best of Text Adventure, or early graphical games, best early RPG's..etc.
When I think of really old games I want to play on a modern system the one that comes to mind is Beyond Castle Wolfenstien. Maybe that is earlier then you mean but honestly I'd pay 5 bucks to play that.

If you go back to the age of CGA you also go back to the days of the Commodore 64 and Atari 800. Both these computers gave 16 colour 4 channel sound.
So I say why buy a 4 colour CGA PC version of a game like Neuromancer (a great cyberpunk RPG) when you can download a free floppy version (.D64 files for C64) and a free Commodore 64 emulator and play the same game with 4 times the colour and more detailed graphics and great REAL 4 channel sound instead of PC speaker beeping music?! :)
I say this as someone who still has his Commodore 64 and floppy and still plays his 20 year old C64 floppy games like the above and Stealth Fighter and Maniac Mansion, etc! :)

I'd love to see some of these games, but even with these very old games, some license holders may have trouble with the pricing, they may charge more than people think its worth (would most people be WILLING to pay 5.99 for a game that is 15 years older or more?), or it may get placed in obscure bundles that have games you might not be interested in.
Also Im sure its probably more work to make these games compatible.

Downpheonix - once you get to DOS, it doesn't matter, as DOSBox will run all DOS games from 10 to 25 years old! I think where it will be difficult for GOG is the Win95 and early Win98 games. They are less likely to work in compatibility mode and would be tougher to get working. There is a win95/early win98 game by Microprose called 7th Legion that I have never managed to get to work in XP, and where no one on the web has either! Later win98 games are much more likely to work in XP or at least in compatibility mode.
So DOS easy, win96 definitely not, early win98 so-so and late win98 easy

I'd pay good money for Qix.