You can look as hard as you wish, you'll probably be too soft anyway.

Wouldn't be easier if this was apart from the "gog store", like inside a personal profile?
Then there in the profile you can manage your collection, show what games you own from GOG, what you own from retail, etc. And there you also set your preferences, recommendations, to share your collection or make it private, and so on...

Did anyone mention sorting the games on the shelf by genre or alphabetical order?

More testers and testing
Ok, I've been thinking about this for a while, and I think it's becoming clear that GOG needs to have more testing for some games before release, and with more testers and system setups. Dosbox games are ok, but a lot of the early 3d period games that have been released recently have run into major problems.
In the long run this isn't good for gog, as if a new customer buys a game on gog and then it doesn't work, they're unlikely to come back.
Clearly there are too many system configurations out there to test on every one, and even new games don't work on evey system, but a lot of the problems have been predictable ones that were known about even before the game was released here.
IMHO gog should do something along the following lines:
1 - Be sure to check the existing fanbase for the game and find out what the main problems are. (eg: i76 framerate and ai/mortar problems).

2 - Recruit a few of the forum regulars / affiliates as testers and moderators, and then give them the game in advance and for free to test. (with an NDA if needed)
This way they'd encounter the main problems earlier, and could either fix them in the release, or have tools ready to fix them once the game releases. They'd also have a few knowledgeable people in the forum, ready to help people if they hit problems. And they might learn about a few useful fixes from the community.
3 - Be sure to have a moderator or staff hang out in the forum of recently released games, and collect all problems and fixes into a FAQ at the top of each forum as soon as possible. A few users have done this, but it isn't official so it often isn't stickied... this means it can be hard to find a fix, even if others have already found it. Leading to many questions being asked over and over.
4 - If possible, update the download with fixes as soon as possible.
5 - Put a link to the FAQ and the support forum in the installer/launcher.
6 - If possible, put a "troubleshooting tab" on the installer that contains the main problems found in testing, and the main fixes. (eg: cpugrab, fps limiter, specific drivers or whatever).
7 - Try and find out who made that FPS limiter java applet and buy it and update it. ;-)

This is minor, but I'd like the installers to have an option to customize the menu location for each game in the start menu (instead of just lumping everything under GOG.com). I realize you can just move them, but then if you uninstall one it has to be manually deleted from the start menu.

It would be nice to see Linux and MacOS X versions for games that use DOSBox as Windows compatibility layer.
This may not be high on the priority list (as someone said "Linux users will figure out how to make it work and Mac users are used to being ignored") but it would be a nice touch.

I'd just like to see more color cheme options for the community section besides two shades of gray. And maybean easier way to reach the game suggestions section, like a button on the main page.

This thread is big.
I know it will require some work, but Is there a possibility GoG could edit their post and make a list of short descriptions of all the features that have been requested in this thread, but not (yet) implemented?
That would be my 'feature' wish

Definitely a requirement needed to add in when a game was last updated (as mentioned numerous times). I was just trawling through some of the forums only to stumble upon a couple of games having an update I wasn't even aware of, and not even a sticky on the posts.
Even if we can't get automatic notification, can it at least be put on the information page for the game the date the installer was last updated? That way (even if it is still a bit long-winded) you can check the date of your installer file against that date to see if it needs downloaded again.

I have a proposal for information about the game on its tab. Concerning the relations between the various titles. The example of BloodRayne is presented in the image from attachment.
The new "bar" called relationship shows precisely these relationships. Bloodrayne Bloodrayne 2 is a precursor, which in turn is the sequel to the first part. When you click on the arrow to open a card game related, this relationship could be implemented in many games at the GOG (although I know that this is a lot of work) designation may apply to previous and subsequent parts of the game, and example information that the game is an addition, or mission pack to another, etc..

I'd like general GOG gift certificates you can e-mail to your friends.

1. Paypal FTW.
2. One of the first things I looked for was a means to have people vote for games that they would like to see. After finding the Games Wishlist (kudos), I saw a few issues with it. There are a fair amount of games listed more than once for an unknown reason. I'm guessing people try to make a New Game recommendation rather than searching first, but implementing a way for users to flag duplicates may help. Also, forcing a search prior to adding a game would help, too.
3. I know it couldn't be the exact same, but perhaps a Features Wishlist could be put out in a similar fashion? Allowing for a simple way to vote for features will streamline the process of what this thread was started for, methinks.

1. What? Paypal is already a supported payment method.
2. As far as I've seen, it already DOES suggest similar already-existing titles when you try to add a new one. Flagging duplicates is a good one though.

I'd like to see version numbers or a date/time stamp on the files I download from GOG.
This way I can see if I have downloaded the latest version with the latest bugfixes/windows 7 compatibility/added extras/etc.
I could re-download files to be sure, but that seems a waste of time and/or bandwidth