I have a very useful idea: sharing wishlist.
Just one example: within few days one person will celebrate his birthday and he want to receive GOG games as a present. But friends don't know game titles that he want. So, they can go to gog.com/users/person/withlist (or any other link), look at his wishlist and buy a present to this person :)

That would be pretty good. And it could get people who would never know about the site interested.

Something to add:
http://www.gog.com/en/forum/general/suggestion_screenshot_labling_for_bundle_game_releases
I was recently looking through the screenshots on the GoG webpage for Lords of the Realn Royal Edition was was struck with the fact that I could not tell which screenshots in the list came from which game.
Would it not be possible for GoG to lable each screenshot (in a bundle release of course) with the specific game/expansion that its attached to. In many cases the newer game can be quite clear when compared to the older, but often there are times when both releases are very similar in appearance, making it hard to tell the look of each indevidual game

I would like to see md5sums and sha1sums for the installers. The installers seem to do an integrity check, but after a looong overnight download, I would like to check if the download is OK before firing up the installer.
I haven't read this whole thread but I did do a forum search and it didn't find any results for this

I've noticed a number of flamebait topics being created by trolls.
Perhaps moderators could be active with +2 scissors of flamebait clipping? That would help the forum community grow.

A very simple one, maybe I missed how to do that, but I would like to have the ability to remove games from my wish-list.

I haven't read any other posts on this thread, but maybe the ability for our own user pages others can visit? That way we can personalize our GOG experience and just show off our hobbies and stuff.

We're certainly lacking the "log out" button at the top of the page. The only place where it appears is the "My account" section, which makes it very inconvenient to navigate to every time.
And by the way, I love Good Old Games! All the childhood memories in the palm of my hand... yay!

Still living my childhood memories, and won't stop until...say around 6 years.

This can already be done, but I think it is easily missed as I too didn't spot how to do this to begin with.
On your wishlist page, tick the box(es) next to those you wish to remove from your wishlist. At the bottom of the list you will then see a Remove button. The button is only visible if you have at least one game ticked.
I'd like to be able to edit my username (just to capitalize the K).
When I registered I thought I'd have to use my username to log in, which is why I used all lower case letters. However, on finding that my email address is used instead and the username is only for display purposes, I'd like to be able to edit it.
I'd also quite like to see download sizes on my wishlist items too.

Don't know if it has been already discussed (this thread is starting to get quite long) but I think it would be useful to know for each game if it supports multiplayer, lan or coop mode

Hey , i've done a search and reading but couldn't find someone asking this.
Is it possible to receive a list of all the latest posts.
Or maybe there's a funtionality that i havent discovered yet.
I mean Instead of clicking every possible topic and the subtopics , i would like to have a summary of all the posts i didn't read yet.

Ability to filter out games you have already bought when browsing the games list.

That's a good idea. I'd like to be able to gift games to other people. I don't quite know if this is possible or not, but It would be nice to be able to buy a second copy to give to someone else's account.