Draw Distance
Guild Wars implements a level-of-detail effect, with more detail being rendered close to the player than far away. In the distance, detailing such as plants is reduced or removed, and characters are rendered to a lower-quality. This drastically increases performance, but doesn't really scale - so high-end cards won't render much further into the distance, wasting the power of the card.
On the left is a hill rendered at a distance, containing just a few tiny plants. However, as we approach that area, on the right, there's clearly far more detail, such as the small bush to the left of screen, that was never rendered originally.
Anti-Aliasing
We tested anti-aliasing performancewith this reference shot:
We got the following results:
1280x1024
These are shots taken at 1280x1024 resolution, with 2xAA applied to the image on the right - you can see the better quality clearly! The right-hand edge of the column is visibly smoother, as is the tip of the tree branch.
1600x1200
These two shots are taken at 1600x1200, with 2xAA on the right. I think that 1280 with 2xAA looks a little better than 1600 native, but obviously 1600 2x is the better image quality.
High Quality Images
These shots enlarge to full screen. The left one really shows off the gorgeous effects that the engine is capable of, but the right really shows up how bad the textures can get in places - they look great from a distance, but up close, they can really be lacking. These shots were taken at 1600x1200 with 2xAA.