I also noticed that my PC that seemed to be rather quiet elsewhere in the house now suddenly seems markedly louder in my room, where it's on a desk.
That can also be because you are in a quieter environment - it seems louder, because your noise floor is lower in the studio. Also, try keep the PC a little away from boundaries like walls (and especially corners), which bounce the sound right back to you, making it seem louder. A little absorptive material on any nearby boundaries can help too.
I find that I'm rapidly running out of desk space also, with the MIDI controller keyboard, PC keyboard and CR computer monitor all competing for space.
LCD screens are a must, not only for how much space they free up, but also to cut down on lots of interference. Space, I'm always struggling with (see below). I've been planning to build a fitted desk for over a year, but don't have the time.
I also noticed Nick's amp on a stand, and remember reading somewhere that this improves the sound. Is this so?
Depends on what you like. It moves the amp/speaker/mic away from a boundary (the floor), which helps cut down on bass boost and reflections a little. In the case of a smaller amp like Nicks', you often want the extra bass boost (his is raised, but in a corner). From a player's perspective, an amp stand usually tilts the speaker so it beams directly at them, letting them hear themselves more clearly.
