Well I did some extra work, and have the money to buy a new PC. It's a long, long time since I bought one, so I'm fairly out of touch.
Most of what I do is sample based, so I'm not going with the very fastest processor, but I guess I need a lot of RAM for loading the heads of samples. Most places here in the UK seem to only do up to 12GB RAM. I found one company doing 24GB, but it would cost me about $1000 dollars more than their 12GB machine.
It's going to be a long time till I buy anything else, so I want to make sure I stretch myself to what I really need, but I just thought I'd check what people's experiences are. Does adding more RAM really continue to increase the number of sampler tracks you can use (I'm using VSL player, ARIA and Kontakt if it's specific to different intruments) or is there a limit to the improvements? I have three 32 bit machines which can share the load, via VEPro, but it would be nice to be able to load a much bigger chunk on my main machine.
And are there any issues with using that much RAM? I'm wondering why other firms don't seem to be doing it - I've already bought from a couple of firms who were probably overreaching themselves to gain the edge over others, and have built some fairly unstable systems.