Update: If you are using Parallels 7, then don't follow the directions below. Just install it normally; it'll run correctly without any tweaking
I spent some time playing Fallout: New Vegas in a Windows XP VM today (Parallels 6) - and the experience was quite good. Here's the setup I have, for those who might be looking to do the same:
- 13" MacBook Pro, Fall 2010 model with 4 GB of memory and 250 GB of disk
- Parallels 6
- A Windows XP, Service Pack 2 VM that's been given access to both cores, priority, and 2 gb of memory
- Additionally, I had to register for the New Vegas Forums, and download the d3d9 dll from there, and drop it into the New Vegas folder (under the Steam directory structure).
Before I added that DLL, the game ran right through the opening movie, and then crashed. Afterwards, it ran perfectly. I did reset the graphics to "Low" from "Medium" - even at that setting, it looks much crisper on my Mac than it does on the Xbox.
The gameplay seems fine, although there is a bit of an odd delay going into VATS at times. Since the whole game slows down, it doesn't result in my character getting killed, so that's ok. As to stability, I've only seen one crash - and given the noise you hear about the game crashing on regular Windows boxes, and some of the instability I've seen on the Xbox, this doesn't worry me much.
The good news? I have access to my current favorite game when I travel now :)