Let's see...the middle iMac with a 17" LCD is $1499, or $1624 if you get it with 1GB RAM. The iMac is touted for everyday use and is excellent for Internet, email, MS Office, iLife apps, etc, and good for most games. Very few power-gamers are gonna settle for an iMac. Apple is wise to provide the best bang for the buck to the 95% of consumers who don't care about Doom 3 frame rates (like me). As mentioned before by several writers, if you need a machine to satisfy your power gaming desires, you need to get a PowerMac or a PC.
Dell is touting its new line of XPS systems to power gamers. These systems start at $1599 (after $400 instant discount and incl. a free low-grade 17" LCD), but that's before adding XP Professional ($79) and doubling the RAM to 1GB ($80). Want a 250GB HD, add $120. Want a DVD R/W drive, add $70. Want speakers, add $40 or more. Optical mouse, add $10. Wireless Card (Bluetooth), add $49. Upgraded 17" Ultrasharp monitor, add $109. The XPS systems come with a 256MB geForce 6800, but add $$$400 if you want a radeon X850 XT PE! And, lets not forget that you don't get OS X on a PC; you don't get iLife; and you have to pay for all that software to protect you from Windows viruses, spyware, malware, etc.
Face it! If you want a pro gaming system you have to pay for it...and it costs more than an iMac. I for one have no complaints about the new iMac - other than that fact the mine won't arrive until next week!
