"Hide all posts written by anonymous" is right up/down there, and it's on by default. What is the problem?
Also, not to derail, n-thing demos and lossless soundtracks. Actually, my stance on lossless soundtracks is: "fuck yes!" ;)

Wishlist.
Paypal.
Video clips of gameplay.
I think thats about all for now.

I would like to see content mirrors a la Steam. I know it's probably not a big deal for most people, but in Australia our internet infrastructure is very poor (due to huge distances and sparse population) and as a result we are given small download limits and if we go over it, our speed is slowed to dialup. The great thing about Steam is all content is mirrored on my ISP's server, which doesn't count towards the limit, so I can download as many games as I like without worrying about it going towards my cap. I am currently shaped, and as a result I will have to wait a week or so before I can download the games I've bought from GOG.com (Which will then immediately put a dent in next month's quota).
Love the site though!

How about user-submitted walkthroughs or FAQs?

It'd be great to see some sort of multiplayer matchmaking or really any kind of multiplayer encouragement for these older games. Even if it is just a shell for Hamachi or something like that.

Haven't dug through this thread yet, but I'd love to see some additional profile customization. Stuff like interests, favorite games, etc.

It doesn't matter they are hidden, it's that it shows they didn't have to register to post and that this could lead to spam and allsorts clogging up the system, seen or not!

Windowed Mode capability in old full screen only games.

Yeah, I'd love to see this.

+1 for the multiplayer match making services. Quake anyone?

Could we perhaps have a dedicated forum for games we'd like to see here? The current thread is really filling up, which usually leads to a lot of repeated requests.
Plus these are all old, beloved games that many of us have heaps of history with. It's easy for us to start blabbing about them, but a thread like that isn't really the appropriate place.

download resuming... or is it just my download manager that's not working?

A light-weight download manager, or having the game-download split into (optional?) chunks would be rather handy. I know not everyone wants these, so options are good, but understand are not always viable.
As has been mentioned, Australian broadband is rather... shall we say poor quality, expensive and capped rather low. If this was a blog, that comment would descend into profane ranting many Aussies here may agree with.
I'd go bald if a Gig++ download cuts out at 99.9% and became unable to resume.

I'd like to see the ability to jump to the forum to see what other users are saying about a title, from the description page. sometimes the reviews aren't enough, I want to know what is bad about a title, what it is incompatible with, before jumping in. I know there are a few people who bought fallout 1 and 2 to find out that simply, their computer could not render it correctly (too fast, too slow, incorrect graphics), and seeing where some have travelled before can weigh on my decision to purchase a game or not.