For me it is Surface 8 for around $1100. I think this would be a great laptop replacement and also a killer tablet.
I already have a couple of Android tablets so I don't see replacing those with a Surface RT. Based on what we currently know they seem to be about the same thing. Unfortunately experience with a WP7 leads me to believe the current state of apps on the RT platform is going to be way too far behind to switch at the moment.
There's no way I could pay more than $750 for the top of the line model. If I'm going to do more hard core computing then I'm going to sit down at a desk top and get work done. To me tablets need to be flexible, have a ton of battery life and be priced less than a powerful desk top.