First of all, gog.com is a great site and I applaud the people behind it.
Now here is my wishlist:
+ Bundles, ie 4 for the price of 3, and/or series like Simon the Sorcerer 1-3 at a reduced price. I have noticed that you some time have limited bundle offers, but standard bundles would tempt me to buy games I wouldnt otherwise consider.
+ Mac and/or Linux support where possible
+ Icon to display if the game runs using DosBox, ScummVM, Native or other.
+ Delete posts in this thread where users are requesting games and not features :p
+ Re-re-rerelease priced games for free (hey, its a wishlist!)
I agree from the previous things and also would like to add:
+ Support for Linux through Wine (or any other tool), it'd be awesome if you can also provide install scripts, or even something like an Ubuntu repo with them
+ Have a place in each game card to discuss how to make the game run through dosbox, wine, scummvm in other platforms
+ Add a different badge if the game is tested by te GOG.com team, the community or just a link to the corresponding appdb.winehq.org page.
+ Deal of the day (it's so tempting xD)
+ Wishlist for share (in a link and rss at least)