You can build a very capable gaming PC that will cater to all your photo and video editing needs for $600 - $800. No laptop in that price range will do the same. And going up to $1000 will net you a rather high end build that should easily max even games like BF3 at 1080p/60hz.
I'd say if it doesn't ever really leave the house, go with the desktop. Laptops are just no worth the money, especially if you have a smart phone or tablet that can browse the web on the go.
Macbooks are fine if all you're going to do with it is dick around or record some music. But the price premium is pretty outrageous, for the same price you could build yourself an outstanding desktop with a lot of change left over, especially when you consider that the half decent MBPs start at around $2000. Yes, you can dual boot Windows, but you could have built or bought a much more powerful machine for half the price, so the value consideration isn't really there.
I've been without a laptop for about 2 years now, and I don't miss it even a little. There's not really much place for them anymore; they're not mobile enough to compete with the convenience of tablets or smartphones while being too expensive and underpowered to be worthwhile for high-performance tasks. Unless you work a lot on the go, laptops are just not useful any more.
A desktop is a good investment right now. They're easy to maintain and always upgrade-able. It may be wise to wait for Haswell to drop (Intel's new CPU/Mobo specification) and compare the market then. I don't expect huge speed increases (10% on the upper end, I'd say) but they will likely be releasing new CPUs for that platform for another 2.5 years. Socket 2011 isn't going anywhere any time soon, though, which is the enthusiast spec.
And if you want OSX, you can always build a Hackintosh and get the best of both worlds for much less ;)
@ZNP: yeah, MBPs aren't as reliable as people seem to believe. My friend takes extraordinary care of every device he owns, yet his MBP and his girlfriend's (2010 and 2011 respectively) have had to go into the shop at least 2 times each before the 2010 finally kicked the bucket in January. His Apple fanboy-ism is beginning to wane, so to speak :p
<message edited by LightofDarkness on Thursday, March 28, 2013 3:27 PM>