I believe it will be down considerably despite the N3DS, not down just a little because of it.

Dedicated handhelds are quite simply going completely out of fashion, the 3DS has had two major revisions and some truly massive, system-selling software release and was down yoy in 2014, comparing the first six weeks of the year (including half a week from the end of December in both cases), the 3DS is up about 200k due to the launch of the N3DS in the west, with a 430k-ish increase due to these extra sales (likely more since the overall weekly sales were a lot weaker in the weeks before, it could be down was much as 250-300k or so yoy already). Before the launch of the N3DS; the 3DS was behind yoy globally by a fair bit and down 5-8% in Japan, the most important territory for handhelds, and after the N3DS launch.

The N3DS coming to Japan did not stop the decline and it will only get worse, launching in the west will not stop a decline either and will likely slow it down even less than in Japan. There isn't really any software on the horizon that is bigger than some of the mammoth hits already released on the platform either, it is perfectly reasonable at this point to expect a considerable drop in the 3DS' sales yoy. Once the launch effect of the N3DS settles, we'll see where the baseline settles; I'm thinking it will be below 2014's numbers and that this difference will increase as the year goes, eventually leading to a 15% drop or more in totals.

PS4, Xbox One and PS Vita will be up. Wii U and 3DS will be down.

PS4 is probably going to sell more than Wii but second and third place home consoles will both be lower than PS360.  PS4 can't make up for WiiU unfortuneatly.  You're going from an 85+m selling third place console to a 20m at most selling one.

All up except Vita and 3DS.

PS4 & XOne should be up, Vita probably, Wii U maybe, but 3DS will not.

PS4 and X1 definitely up.
Wii U also up, but only slightly, but it'll still be celebrated by this forum of course.
3DS down, maybe not as heavily as last year (due to N3DS) but still down.
Vita...I dunno. Maybe up due to China.

Oh please.

3DS is now up by nearly 90% in the US, is down by 5% in Japan (In Japan!!!!!) and of course is massive up even in Europe.

Now, nobody can know what will happen, but said NO CONTEST is ridiculus.

And how much of that 90% is due to N3DS having released two weeks ago (in current front page numbers)? Launch weeks for consoles is nothing to base predictions off of, the Wii U had great launch numbers, better than the PS4 in Japan. I thought you would have figured the same, or is it just an oversight?

If the 3DS is down 5% in its strongest territory by far after the N3DS launch, what does that mean is likely for the west where the sales have been notably weaker for a long time?

It will be down for the rest of the year. It is an ageing system now and there is not many, if any, system sellers on the way.It is up now because of the new model launch, but most weeks this year will be down form the same point in 2014. Especially the holidays will see a significant decline.

it's useless write you prediction.

As i said, OF COURSE 3DS can be down, but said that is IMPOSSIBLE that will be up not have sense.