I like Joyceys idea about optionally being able to show off your collection to others.
I'd quite like to see what posts I got + and - rep for, obviously not who gave me the rep but be able to see a link somewhere saying.
You got +1 rep for this (Link) post or something.

Another feature I'd like to see, now that we have shelves, is to be able to check each game that I have finished (among games I've bought).
Fallout: Finished
Fallout 2: Finished
Lure of the Temptress: In progress (or sth like that)
Or just a small box for each game on the shelf for users to write some info down.

Hey there,
So i was wondering if you GOG.com guys could get classics like the "Lands of Lore" series,
"Project Eden", the "Swat" or "Police Quest" series, the "Kings Quest" series, "The lost Vikings", "Commander Keen", "Serious Sam", "Heavy Metal FAKK2", the whole "Elder Scrolls " series (the old titles up to Morrowind), the "Might and Magic" Series, the "Ultima" series, ah, and maybe the jolly old "Deus Ex".
Also try to get "Day of the Tentacle" and "Maniac Mansion" :P

Did you vote on the wishlist for those??

I too would love for Lucasarts games to come on GOG.
The id games are available on Steam, I doubt they'd come on GOG too.

I would also like to see covers introduced.
As for the new game shelf display? Nice touch, it looks really good.

I want:
Syndicate
Syndicate Wars

Definitely Paypal - I don't have a credit or debit card so it's the only way I can pay.
And the ''in depth user profiles'' have got to ahve a section to show off your rig and existing games collection

What I would love to see is an indication on each game which (if any) emulation or engine re-working system (such as DosBox or ScummVM) is in use for the game and the option of downloading a zip file with the game files in.
Games like Simon the Sorcerer etc. run just fine on any system that ScummVM supports yet the GoG installer gives users an extra unnecessary hurdle for those not running a Windows system. (the installer screen suffered some display corruption under Wine on my system)
Aside from that, GoG was nice and easy to use - I'll definately be back after finishing StS :)

Seconded! An "expert" option to download as a zip file would be fabulous. I'm on Linux, and extracting the game files from the exe is a hassle (though the game runs surprisingly well under wine ;-).

That's already a feature.
That'd be nice!

Social Stuff:
Inviting friends to this site.
Adding them in some sort of contact list.
Be able to view their profiles / shelves.
Maybe sent messages or add a guestbook/shoutbox.
Background information, reports, articles:
how it is to try to get a hold of old games.
which companies are generally clingy and won't ever release here (Lucas Arts?).
reports on companies gone by (Bullfrog).
Sneak Previews:
You pay 5$/month and get a surprise release each month... a week before it is in the store.
You cannot tell what you're going to get each month, but maybe you can influence the genre.

More abandonware!
If GOG cannot take money for abandonware games, introduce a donation service:
Announce that a certain game will be made available for free download (with the usual GOG service & XP/Vista compatibility guarantee) as soon as a certain amount of donations has been made (Like the blue donation bar on wikipedia) to cover the basic release & maintenance costs.

Dear rmaertin, I think you mean freeware. Abandonware is an abstract concept and GOG cannot put games that are left without support by the developer on the site, as it would be against copyright laws.