Seconded

Also, I hope the Total War series would make its debut on GOG this year.

Big ones (i.e. hard to achieve): Dune series, Drakan: Order of the Flame
Smaller: Submarine Titans, Fury of the Furries

Any of them would be great.

LAN-mode for all multiplayer games!

I don't think that will happen for a very long time, but I do agree with you
I agree with you there on that, my wife and I like to play games together.

Tell that the developers/publishers.

A truly working and bug free website.

bioshock classic releases (or a workaround for bioshock "windows 7 platform update"). i mean i could install platform update for 4 games out of a million:-

turok 1 - directx 11 + platform update OR opengl renderer - untested
turok 2 - directx 11 + platform update OR opengl renderer - tested
bioshock 1 - directx 11 + platform update OR classic - partially tested
bioshock 2 - directx 11 + platform update OR classic - partially tested

main reason being the BSOD of platform update on AMD hardware & notebooks. even though i have switched to nvidia since, i do still own notebooks, these have ancient drivers courtesy of manufacturers

Games: Never going to happen, but Diablo 2 would be nice. :)

Site features: I would like to be able to move things in my collection, so I have games of the same franchise grouped together, my favorites at the top of the page, and such. I have my games organized this way using tags, but that's a very annoying and time consuming workaround.
I would like the same feature for the wishlist, so I can organize the games I want in order of preference.

Would love to see the Drakensang games here.

More Crapcom games.

I like to see GoG roll back the front page (especially during sales!) to the way it was just prior to this.

That last redesign started off a little rough (a lot of scrolling at times) but by the end it was pretty darn easy to navigate sales in easily digestible pieces.

This new setup is terrible. I usually love browsing sales, here it's a total chore - seriously digging through 40+ pages of games? Which no way to "jump" to pages so even if I want to sip a cup of coffee and check out say, pages 15-25 I have to click through an insane amount. It's cut down my game browsing (and hence impulse buying) quite a bit.

Games I'd love to see: Obligatory NOLF 1+2
But now that Bioshock has shown up, I'm feeling even more hopeful the second new XCOM game might end up here sooner than later. I played the first on console, would love to try 2. I'm sure there are others, but those are the two that jumped out...

... oh maybe Freelancer is up there too ;)

And how about a surprise Fade to Silence release! Make it happen Thom!

my personal preference would be all games on a single page. it may be resource intensive for some users, but that's what i'd do