Long Interconnects or long Speaker cables?

I'm considering whether it's better to use mono block amps close to speakers or close to pre-amp. The distance between the furthest speaker and preamp is about 4.5m, so either the speaker cables would have to be about 4m, with 0.5m interconnect or vice versa.
Current set up uses longer speaker cables.
Has anyone experience of the situation with long interconnects?

Hi Ian,
When I had the Proprius amps on demo I noted that so they can be used near/attached to speakers and because they have balanced connections the length of cable was not an issue unlike unbalanced connections. How much of an issue unbalanced connections are with long cable runs I do not know but I was always under the impression that the shorter the run, the better.

.....the balanced out card option used on Reflex and Revelation phono amps....

This is an interesting tidbit I had not noticed mentioned elsewhere yet ?

Thanks all for the input. I tried the Proprii on loan some time ago, but wasn't able to try them close coupled to the speakers; I'm sure it would have been even more impressive. In an ideal world (ie finances permitting) I would foresee an Aria pre-amp with balanced interconnects driving a pair of Proprii attached to the speakers.
In the meantime I am trying to get the best from my existing mono block amps and the dilemma is whether to invest in Interconnects or Speaker cable. My amps have SE and balanced inputs, but my pre-amp has only SE outputs. My speakers are Dynaudio Geminis which are nominal 4 Ohm, but do dip down to only 3 Ohm.
As I was thinking, it seems the best solution is to close couple the amps to the speakers and use balanced interconnects - all I need is the balanced interconnects and and an SE to balanced buffer to drive them. For now I shall try SE interconnects, before deciding on the next move.