Good call Hamister about 64DD being a useless addon. I think we should leave Virtual boy out of those 2 categories because it deserves its own category.
Bad console idea to begin with - Virtual Boy, Sega 32X, Philips CDi

@dgm6780 and ikilledkenny
When it comes to controllers, one mans trash is another mans treasure so I'd leave those out of the equation. I personally dislike the Dpad on a PS2/PS3 controller with a passion but the rest of the controller is amazing.
On the other hand I think the Saturn controller is the best controller ever made for 2D games and I still use it to this day to play street fighter.

Also adding Turbographix and master system to no third party support.

1. Price too high - Sega Saturn, PS3, 3DO, Neo Geo

2. Lack of games available at launch- Sega Saturn, N64, Sega 32X, PS2

3. System reliability - Xbox 360, Ps2, PS1, Atari Jaguar, Atari 5200

4. Pointless Ad-ons - Sega 32X, Jaguar CD, 64DD

5. Difficult to program for - PS3, Sega Saturn, PS2, N64

6. Lack of or bad copyright protection to prevent piracy - Xbox 360, Wii, Dreamcast, 3DO, Sega CD, PSP - While some of these had copyright protection, for those systems listed it was broken in less than a year

7. Short Supply - Wii, PS2

8. Unnecesssary Censorship - SNES, n64

9. Allowing only 3-5 games per company per year - Nintendo - what system?

10. No 3rd party support - N64, Sega Saturn, Tubographix, Master System, gamecube

11. Sticking with Cartridges - N64

12. Awful PR - Saturn, PS3, Jaguar

13. Gone mad with power (thinking technically superior means best) - PS3, Jaguar, 3DO, Neo Geo

14. Bad console idea to begin with - Virtual Boy, Sega 32X, Philips CDi

Looking at the list, 2 things are clear... Sega Saturn went wrong in almost every aspect that matters possible and it explains why Sega went from industry leader to out of the console industry. Other than the short supply, Nintendo did their homework with the Wii.

Another category could be "not delivering on the hype" - the only system I can think of that never really did anything of what it promised, was 3DO. It was hyped as an über powerful system with set-top-box abilities making it a complete multimedia center (I think it was said to be 50 times as powerful as the 16-bit systems). The end result was far less impressive, with an under powered processor and virtually no multimedia abilities.

could anyone explain why dreamcast failed?

@pichu
Dreamcast failed because it had no third party support, and Sony was able to kill all Dreamcast hype with the PS2. Also, there was lots of ill will towards SEGA from their stupid moves with the SEGA CD, 32X, and Saturn.

^ gamecube also had no third party support but it didn't instantly die like dreamcast. the PS3 hype also made many people thought PS3 would win this gen but look at it now.

One could say Dreamcast failed because of piracy, or because PS2 hype was unstoppable. I think at that point, because of Segas history and financial shape Dreamcast was doomed from the start...it was Sega's Swansong and im glad they got it right at the end.

Imagine if the original Guns n Roses got back together for one show...they know their time has passed but here is one heck of a party as a good bye. That was the Dreamcast...

Left out Xbox from Mad with power list.

Do people agree Xbox should be put on mad with power? I don't remember too much hype about how powerful the Xbox was. 

No one ever told me Xbox was the best because its most powerful...i heard a lot of "Xbox is the best because it lets you play online." And after bying it I remember saying "umm no, while cool its still second best" to those people :)

only one really matters, and that's not enough great exclusive games. Dream Cast, X-Box, 3DO, and every other console that failed or will fail.