Martin,
Scene capable hardware works far better than any software as far as performance and affect. I have both and only use software where needed, If you invest in good scene capable hardware take advantage of it.

Jeff I have just done most of my house in X-10, I used all switchlinc switch's (pcs are also very good), you will need to get a good quality phase coupler/repeater and some filters for a proper system. Check out Bill here, http://www.homeautomationnet.com/ he is a fantastic supplier and will guide you in the right direction