In an upcoming episode of the Cool Tools Show podcast, I tell the story of how I wrecked my iMac by trying to replace the hard drive. Instead of buying a new iMac, I bought an Acer G257HU 25-inch (2560 x 1440) display and connected it to my MacBook Pro. I actually like this set up more than having two different computers. The display is gorgeous and the brightness can be cranked way up if you need it.
For $(removed) I have no complaints about this monitor. I wouldn't complain if it had cost $(removed) I'm using a $(removed) Thunderbolt-to-DisplayPort cable to connect the laptop to the display.