The basic configuration would be as follows:
* iMac with Intel Core i5 processor (I5-750) @ 2.66Ghz * Built-in 27in LED-backlit glossy widescreen TFT LCD display with IPS (up to 2560 x 1440 resolution) * 4Gb RAM DDR3 PC3-8500 (1066Mhz) SDRAM SO-DIMM * 1Tb Serial-ATA hard drive; 7200rpm * Slot-loading 8x Dual-Layer SuperDrive optical drive -- reads/writes/rewrites CDs and DVDs * ATI Radeon HD 4850 with 512MB DDR3 SDRAM; PCI Expresss * Built-in iSight camera * Built-in stereo speakers, built-in microphone, headphone/optical digital audio output, audio line in * Built-in 10/100/1000BASE-T (Gigabit) Ethernet * Built-in AirPort Extreme wireless 802.11a/b/g/n * Built-in Bluetooth 2.1 + EDR (Enhanced Data Rate) module * 1x Secure Digital slot (SD) * 1x Mini DisplayPort * 1x FireWire 800 port (up to 800 Mbps) * 4x USB 2.0 ports (up to 480 Mbps) * Apple model: A1312 (EMC 2374), MB953, iMac11,1 * Apple description: iMac (27-inch, Late 2009) [codename "Nehalem"] * Introduced: October 2009 * Discontinued: July 2010