Good for you Mahgi. I agree, cables represent a very minor part of a system. They are either good cables or they are not. It is also easy to make your own cables of the highest performance and save thousands.
There is a point of diminishing returns with loudspeakers and I put it in the 40-50 thousand dollar range. This does not include subwoofers. I know of no vintage loudspeaker (pre 1965) that can hold a candle to the best modern speakers. Upgrading loudspeakers will also generally not solve severe room problems although some types of speakers interact with the room to a lesser degree.