Success in this case is not a one dimensional measurement, but overall I'd say yes for the following reasons:

1) It seems to be expanding it's market share in the US and maybe EU, and that is improving it's overall rep.
2) It is keeping most big 3rd party titles (GTA4 the prime example) from being PS3 exclusives.
3) It has so far been able to launch a respectable number of outstanding exclusives on it's own.
4) It is likely to turn a profit this year and through the remainder of it's life cycle.
5) Despite the best efforts of the competition, it remains the console of choice for online gamers.

Of course it is not a perfect success as others have pointed out:
1) Lost large amounts of money it's 1st two years.
2) RROD and related issues
3) Japan

However, issues 1 and 2 are likely temporary and should be put behind MS soon (if not already), while most of the areas of success are likely to expand as we move into the future.

Remember that MS came into this as a 3rd console in what has always been a 2 console environment. Most generations are understood by simple "A vs B" console wars - Atari vs Mattel, Nintendo vs Sega, Nintendo vs Sony. Any attempts to launch a 3rd console has been a disaster (or, in the case of Sony, created a disaster for an existing company). So MS has successfully altered the console landscape for the near future - everyone is expecting all 3 companies to compete next gen. The simple fact that MS has shown it deserves a place at this table is reason enough to call it a success.

Here is my take on the issue...

There is obvious growth from the original Xbox, but most of the growth is linear, so I don't know if it is as much as MS would like. They are finally diversifying the library, but they are not marketing the diversification enough so people still assume its an FPS console. I don't know anyone who knows about Lost Odyssey, Eternal Sonata, or Banjo. Everyone (without exception) that I know that got a 360 besides me bought the system for Halo 3. Over 50% of the owners have Halo 3. While its good to see that kind of attach rate, it shows that the 360 userbase is not diverse enough in their gaming tastes. With the PS2, even for big hitters, only about 10% or less of its install base bought the title whether its GTA, MGS, FF, or GT.

So MS really needs to go the extra mile in diversifying the taste. I can tell you as a 360 owner, because I don't own or prefer Halo 3 (Owned it for a week and sold it), I feel more like I'm "2nd Class" by the company and its fanbase. I'm buying all of these titles on the console that will probably bomb horribly in the market that no other 360 owners really care about.

As far as sales in "others" go, I think Sony really has the advantage whether people want to admit it or not. Weekly Software sales are already higher. PS3 actually just had one price cut in the "Others" region that was two months ago. It's still more expensive and does not have any games bundled with it.

Many people keep saying that "Sony is out of Ammo" or "Sony can't lower the price any further," but we'll see in 2008. I was one of the few people that expected a $400 PS3 by this time. Most people thought Sony was out of Ammo when it was at $600. Their other departments seeing tons of growth and is expected to continue and also there is still some room for cost reduction in some of the Blu-ray components.

So in summary, Sony and MS are both pretty unsuccessful in comparison to Nintendo so far this generation. Microsoft is not as successful as the American press would like us to believe and Sony is not as unsuccessful as they say either. Both are mediocre right now.

In North America yes. Really there has been such a dominant software giant in America in awhile. Kinda reminds me of the N64, where it was a dominant hardcore gamer owned console.

But everywhere else, and somewhar hardware wise in America, as well it has not been a success. MS would have wanted more out of a successor that had a 1 yr lead.

AT the end of 360 life :
27 m NA
13 m Other
1.5 - 2 m Japan

Total = 41.5 M

SUCCESS

It would be a bigger success if it had japan

The 360 is not a success in my book, it's just moving to darn slow, and even failed to gain a sigificant lead despite being all alone on the market for an entire year. That's just poor imo, and their second year was no better than the first.
Even their biggest titles fail to move much hardware.

looks software sales NA i call that good

it is a success compared to Xbox

Still sad to see the WORST piece of hardware (of all time ?) being able to sold so well ... 

what will last forever?

I think Microsoft's major problem is the fact that it's relatively new to the game console market. Personally I think Xbox not being a commercial failure was a great achievement. I mean when I bought my old Xbox I was unbelievably worried that it would be like the Atari Lynx(which none of you have probably heard of). For those of you who don't know the Lynx was released in 1989, it was a handheld rival of the gameboy. It was far too ahead of it's time and was scrapped. Honestly if the 360 finishes this generation with roughly 25% of the market share I would call that success. Plus attachment rates mean software sales for Microsoft could soften the pain of finishing 50 million units behind the Wii.