no, the imac screens are very much hd. it would definitely play in hd if you were to get an hd disk drive.

If it's the 20 inch model, it has a 1680x1050 screen, and if its the 24 it has 1920x1200 screen.
HD resolutions are 1280x720 (for 720p) or 1920x1080 (for 1080p), so if you have a 24 incher you can watch either perfectly. ^_^
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MacBook Pro Intel Core Duo 2.0ghz, 1gb ram
Dell 228WPF 22" monitor
Mybook Premium 320gb
iPod Nano 4gb (red)
Wacom Intuos3 6x11