For those of you wanting to avoid the Apple faggotry, Dell has released a 27 inch Ultrasharp IPS 5k (5120 x 2880) running at 8ms
http://accessories.us.dell.com/sna/productdetail.aspx?c=us&cs=04&l=en&sku=UP275K3. I read it was supposed to be sub $2,000, so you'll probably find it cheaper at other retailers and not off the Dell site. Great for colour work, not so great for gaming.
Personally, I am waiting for the new 32" Asus ProArt PA328Q 4K which should drop sometime this month. First monitor to come with HDMI 2.0, but you'd still want to use the display port.
computex 2014: ASUS ProArt PA328Q 4K UHD Monitor - YouTube
It's a lot like other 32" 4K IPS panels coming out. I hope it's 6ms or less (the BenQ 32" 4K IPS is 4ms) and so should be good for both colour work and gaming. Expecting it to be about $1500-$1700, plus a couple new GTX 980s to drive the thing.
BenQ's 4ms offering...
http://orwww2.benq.com/product/monitor/bl3201pt/
Taking preorders for £899 on overclockers.co.uk. Nice balance of colour accuracy and performance for gaming.
Samsung's 8ms offering...
U32D970Q - 32" 970 Series UHD Professional LED Monitor
Selling for $1999 but it's not in the wild yet and not great for gaming.
All these 32" are using the same panels from what I understand, with each manufacturer tweaking the hardware and software.