I would only recommend you getting a laptop if you really needed one like for work of projects, etc and Dolphin was just a pass-time and you only wanted to play really lightweight games. The thing about laptops is if you want one that will play Dolphin really well you're going to have to spend a lot of money on one, not to mention overheating issues. That being said, you can get a really really good desktop that will play most Dolphin games full speed for $1000 or maybe even less. It's not only cheaper and gives better gaming performance but you won't have overheating issuesif you select the right case and aftermarket cooler (a really good one is the cooler master hyper 212 plus which is only like 30 and works as good as many other higher priced aftermarket coolers)
The right man in the wrong place can make all the difference in the world.