That's an honest effort but not enough. Throw the Apple Thunderbolt Display and the correct Apple Wireless Keyboard into the comparison and points 1, 3, 4, and 7 evaporate.
You're standing on a single extra key, a logo that might be backlit instead of foil, a different trackpad/keyboard foot arc, and the fact that they used plastic designed to mimic a specific metal with a specific finish. It's not enough for most observers, and HP is right to take some lumps over this.
Metallic Logo: Nope. Appears to be a back-lit logo which is white in color [1]
Logo Positioning: Is similar but not the same. Apple's logo is not in the black frame region. They both are centered though, I give you that.
Aspect Ratio: iMac seems to be 8:5. This is 16:9
Foot Design: http://thenextweb.com/apple/2012/09/10/hp-imac/ Check the last image.
Choice of Material/Choice Of Finishing: Someone pointed out on the thread that HP is using plastic and not brushed aluminum.
Keyboard Design: There aren't many side shots of the smaller keyboard from Apple but [2] looks different from Spectre One.
Key Coloring: White on White vs White on Aluminium Grey.
Key Layout: Is Also different. Have a look.
Keyboard LED: Cannot deduct from image, so I will give you that.
Trackpad Design: Yes similar from top
Trackpad Footing: Check the side shots, they are different
keyboard battery chamber and trackpad battery chamber: Sorry cannot see from the shots.
[1] http://www.engadget.com/photos/hp-spectre-one/ [2] http://images.amazon.com/images/G/01/electronics/detail-page...
Edit: iMac has 16:9 screens as well. So adding that here.