Okay guys which gap will be closed first in your opinion (WW sales)? Examples:

PS3 surpasses 360;
PS3 or 360  surpasses  Wii;
Wii U  surpasses  PS Vita;
PS4  surpasses PS Vita;
PS Vita  surpasses  Dreamcast;
Wii U surpasses  PS3 or 360;
PS4 surpasses Wii U;
etc etc.

Feel free to suggest other gap closings, but try to avoid the easiest ones (i.e. PS360 closing on PSP, etc).

I'll try something bold and say PS Vita surpasses Dreamcast.

I think the ps3 will pass the 360

i think wii u passing psvita is most likely

I think the PS4 will close the gap with the Wii U right after the Vita closes the gap with the 3DS.

Wii U  surpasses  PS Vita;

Didn't PS3 pass 360 already?

This year:

PS3 surpasses 360. (It'll happen sooner since Wii U won't outsell PS Vita unitil Christmas season unless Nintendo slashes its price soon)

Wii U  surpasses  PS Vita.

2014:

PS4  surpasses PS Vita.

PS Vita  surpasses  Dreamcast. (If that doesn't happen it will mean PS Vita is no longer in production)

2016:

PS3 or 360  surpasses  Wii. (It will probably happen sooner (2015) thanks to worldwide appeal and emerging markets)

PS4 surpasses Wii U. (Is it really possible to bomb harder than Wii U?)

Never:

Wii U surpasses  PS3 or 360 (Wii U will be lucky to sell 30 million units lifetime)

PS3 or 360  surpasses  Wii (No chance in hell)

Edit: My forecast is based on shipped units.

At this rate the WiiU will take a long time to outsell the vita, And with the up and coming flurry of jrpgs coming out in japan for the vita over the next 3 months I don't see the WiiU outselling it anytime soon. Maybe the end of the year start or start of next year.

The only upcoming PS Vita title that can move a sizable amount of systems is Soul Sacrifice, the remaining titles will do nothing more than a negigible bump in sales.

Funny question to ask while the Vita is clawing its way down to 25k per week globally.