make sure the HDD is at least 300 GB. Porn nowadays is abundant and extremely available. Last thing you need is to run out of space 'cause you've got too much porn.
Also make sure that there is display brightness control somewhere on the keyboard.. I hate having one hand on my rocket while watching my porn and having to go to control panel, displays, settings, etc, etc. while I could just be fumbling for a single button on the keyboard to prevent me from going blind 'cause the screen is too bright with all the lights turned off.
While you're at it, make sure the display is easily wipeable with no exposed vents near the hinges. You'd think the dudes designing the laptops nowadays would understand that high quality porn results in extremely explosive bursts of happiness. This happiness can get away pretty quick and land in the one place thats going to turn your brand new laptop into a paperweight pretty damn quick.
Oh and make sure you buy the extended warranty, sometimes in the moment of achieving happiness I tend to zone out and have been known to drop things, and if your new shiny laptop should fall victim to Newton you'll need to replace it quick no questions asked.