Memory foam is great, I now have a problem tearing myself away from my bed in the mornings, I always used to be out of my bed by 07.00 everyday now it more like 08.30 if im keen.
Water beds are the worst for causing marriage problems, me and my Ex had one, we soon drifted apart!
Did you find it very warm? Am interested in the memory foam toppers but I'm permenantly cold and man hostage is usually quite warm so I'm not sure it's a good idea really.
I actually found a memory foam topper was great (got a cheapish one from IKEA) - very comfortable and didn't have any 'overheating' problems.
This led me into buying a dunlopillo memory foam mattress (layers of foam over pocket springs), which I really don't like at all - much too hot & has lost its 'bounce-back' quality far too soon ...