Personally, I'd go with a desktop. My current computer is a laptop, which was a half-way decent gaming desktop when I bought it ~5 years ago, in 2009. I previously only built desktops for gaming, but I kinda got out of gaming, so I wanted something portable, for obvious reasons. But most of its life it has been spent on a cooling pad connected to a monitor or my TV via HDMI with wireless keyboard and mouse.
Back then Android sucked, the iPhone seemed huge (hah!), BlackBerry was for yuppies, mobile data was slow, and the iPad hadn't been introduced yet. Then I got my first smartphone in September 2009. It also marked the first time I actually used my laptop as a laptop, which means I took it off the cooling pad, stuffed it in my backpack, and took it with me. Had I a smartphone back then, I wouldn't have bothered with a laptop. And tablets still weren't on the market yet.
Now, I own an LG G Pad 8.3, and I love it. As far as portable computing goes, it does everything I'd need it to. Heck, since it's an Android just like my phones, it many ways it's more capable than a laptop, since everything I do when I'm not at home is done on my phone - or now my tablet as well, with wi-fi hotspot. Is it really as capable as a laptop? It some ways, yes, but it most ways, no. Obviously, if you need a portable computer for school work or business, a laptop trumps a tablet when it comes to ease of use and productivity. But the tablet is just so more convenient. A laptop weighs several pounds, you need the power supply, which adds more bulk and weight. My tablet weighs 12 ounces. It's small enough to comfortably hold and use with one hand regardless if I hold it in portrait or landscape, yet big enough enjoy games, browse the web, watch Netflix, etc.
My next computer will be a desktop, probably after tax season 2015. My laptop's not a complete dog; 2.2GHz dual core AMD, 4GB RAM, dedicated ATI video card with 512MB RAM. But it has its obvious limitations. If I'm watching a video in 1080p, or even 720p with a high enough bitrate, it can't keep up. Hell, the phones and tablets these days make my laptop seem like a dinosaur. Sometimes it takes about 10 minutes on a cold boot to have everything loaded and not lagging. Plus the battery life on this thing is just pathetic, and I have practically zero upgradability on this thing. So I'm buying/building a desktop again. Something that doesn't compromise on performance/dollar. Something I can upgrade. Something that doesn't require a surgeon's hands to take apart and repair.
Frankly, for me, the idea of a "gaming laptop" is and always has been largely an oxymoron. A laptop will always be inferior to a desktop. Space is limited, which means hardware is limited, and cooling is limited. And you're going to have to spend so much more. The screen is small compared to a monitor, and quality suffers. And touchpads just suck beyond tolerance.
I really, really love the combination of my smartphone (even though I hate my current phone) and my tablet. It's the perfect size for eBooks, big enough for browsing/games/video, it lasts for days on standby, and several hours of active use. It can take a 64gb microSD card, so I can load it up with movies when traveling, and even has HDMI-out via Slimport, so I can plug it into someone else's TV if I'm traveling.
FWIW, when I get my next PC, I'm either going to build it myself like I used to, but since I'm so far behind the tech, I might have it custom built (the idea of liquid cooling scares me), and Cyberpowerpc was the company I was looking at using. They do pre-built machines through newegg that might save some cash. I'll have to check out ibuypower though.
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