It may not have a Retina display, but the new 21.5" iMac has some commendable specs:

2.7 GHz quad-core Intel Core i5 processor with 6 MB L3 cache

8 GB of RAM

1TB hard drive (5400 rpm)

NVIDIA GeForce GT 640M graphics processor with 512 MB dedicated VRAM

Four USB 3.0 ports and two Thunderbolt ports

802.11n Wi-Fi and Bluetooth 4.0