It came to my attention that one of the Halo 4 forerunner multiplayer levels features a flow to forerunner architecture that seemed 'eye appealing'. But this is my opinion. If you disagree with what I'm about to say, then that is great. If you agree, then that is also great.
Some of us keep the 'rule of thumb' that forerunner architecture must have sharp edges (45 degree angles for example). HOWEVER, I want to point out that some things can be rounded out if done properly.
Here is an example of corners on a hallway being rounded instead of sharp. This is perfectly acceptable, the same can be said for the towering architecture in the background. The one thing the designers seemed to keep in mind is the use of angles within these rounded corners. I loved how they added forerunner designs along the wall. The way they extrude, intersect, and merge onto the floor.
Circular or smoothly flowing surfaces can be used in forerunner architecture if done correctly. I think the guys over at 343 are going to show us some crazy forerunner architecture that goes beyond our "rule of thumb" thinking.
Conclusively, forerunner architecture is creative in its own way. The use or "rule of thumb" of 45 degree angles being a 'standard' may very well be true, but it does not apply to every single piece of forerunner architecture. Keep in mind that the 'rule of thumb' is a guideline. It should not get in the way of your artistic, creative mind.
Have fun modeling!