GOG is really cool, and the nice thing is (for those of us using Macs) is that some of them are old enough (read: not very graphically intense) to theoretically run virtualized, either through Parallels or Fusion. Fusion's DirectX support is more advanced than Parallels', so I've been using Fusion.
I'm using Fusion Version 2.0, build 116369. The most recent one.
So far, I've tried Freespace and Fallout. Fallout runs nicely in Fusion, you can even resize the window to a more comfortable resolution and the game scales with it.
Freespace works, but not well. It's very choppy and difficult to control your ship. Textures go in and out. Unplayable. But a few more updates to the Fusion graphics driver should take care of it.
I'm downloading Perimeter right now, I'll let people know how well (if?) it runs when it's done installing.
[EDIT] Perimeter runs, but slowly. Again, more optimizations to the DirectX emulator would probably bring it up to speed.
One final note: I know a lot of PC gamers love to bash on Macs. This isn't the place for that. If you don't have something constructive to say, take it elsewhere. Start a thread if you want, bashing Macs, I don't care. But keep it out of this thread, I started this thread to help out Mac gamers, and we don't need PC fanboys telling us that "Mac's are for n00bs." We already know you think that.
The Games That Work In Fusion List:
- Fallout
Games That Kinda Work:
- Freespace
- Perimeter
Games That Wont Launch:
- None yet

I will keep an eye on this thread. My primary machine is a PC, but I have a MacBook for use when I am traveling and would love to be able to run some of the games I buy here on it.

There was a Mac port of Fallout back in the day, I think.

I've been poking around with Lionheart: Legacy of the Crusader on my MBP and it seems to be working just fine.

- I got TOCA 3 running on my iMac 24" quite well with Fusion. It makes odd reflections on the cars, but you turn down some detail slightly and they go away. I forget which setting that was though... Maybe I'll add it later if I find it and others are interested.
I didn't bother trying with Freespace, since there's the FSO port anyway!
As for Non-GOG games:
Age of Empires 3 runs very well once you turn off the glow effect and turn shading to medium.
Age of Empires 2 needs nothing special. This game was where I discovered that Fusion really prefers that you run games on Space 1 if you have spaces installed. Otherwise it was just a black screen.
I must say, Fusion is great!

What about Fallout 2, have you tried it yet? Is fusion free?

Fallout and Fallout 2 basically is the same, so it should work.
Don't know if Fusion is free though.

Fusion is not free. VirtualBox is free, but I seriously doubt it will run games.
I also tested out (non-GOG) Virtual Pool 3. Nasty. It has trouble with mouse speed and especially changing graphics size; if you want this, run it in "desktop window" mode. It's such a great game though...!

Cool, thanks. I will check out Fusion, because I would love to be able to play the Fallout games on my laptop.

Slightly off-topic, VirtualBox is getting OpenGL support. There's a video of one of the devs running Serious Sam 2 somewhere. No idea about DirectX support, though.