I love compact rigs, I usually build Mini-ITX systems, with no spare space in the end. This one is my biggest rig, a mATX gaming system in a 32cm aluminium cube case. The case has been slightly modded so I could fit fans outside the case. Every fan is covered with a grid to give the build a cold industrial look witch IMO goes very well with the brushed aluminium from the case.
Even though I had to use slim rads/fans to get everything fit inside, it's very silent and cool. The CPU can even overclock to a stable 5.00 GHz through gaming sessions, with a bit of noise from the fans of course.