I yearn for the power and upgrade-ability of a desktop because I find myself using a laptop like a desktop 95% of the week. However, that 5% a week that mobility (with all files/programs/VGA & HDMI ports/... capability) is an absolute requirement. I supplement the laptop experience with a large monitor, among other things.
On the comments about laptop keyboards reducing typing speeds - I totally agree, and I am also kinda ticked when I don't have a full num-pad for those high-speed data entries.
On the comments about tablets for presentations of PDF's and so forth - I find myself presenting somethings on my phone that, if presented on a tablet, would enhance the presentation quality dramatically. Granted, some of those presentations are unplanned on-the-spot type of deals, but I guess that is where a large phone comes in. Whether the cost vs. utility of massive and expensive phones is worth it comes down your preference and your situation.