So there's currently 10 cosnoles on the market right now.

6 Home consoles Wii, Wii U, PS3, PS4, X360 and the XOne. 

4 Handheld consoles: PSP, PSV, DS and 3DS.

I was wondering if there has ever been that many on the market at the same time. Also what year do you expect the "Last Gen" consoles to be discontinued. 

I think the DS in '14, PSP in '14. I think the Wii has? X360 in '15 and PS3 in '17

dont really know. though i think the PSP, DS and Wii will be discontinued soon. Maybe the PSP will just stay in japan until 2015. Wii is already discontinued in EU/japan.

I remember in the early 80's there was a rash of consoles that jumped in the the console bandwagon.  You had the Atari 2600, the Intellivision, ColecoVision, Starcade, Vectrex, Odyssey II.  Maybe they were not on the market all at the same time, but they were all during the same generation.

i really need to get a new PSP before they discontinue that thing.

Wii original was discontinued, wii mini was not.

Yes, during the transition between the 16bit and the 32 bit era ( 1995) :

home consoles

SNES / GENESIS / 3DO / JAGUAR / NEO-GEO / SEGACD / PHILIPS / SATURN / PC-ENGINE / PSX / APPLE BANDAI PIPPIN
handhelds :

GAMEGEAR / SEGA NOMAD / GAMEBOY / NEC / LYNX / VIRTUAL BOY

PS. probably missing a few and forgot the names of two consoles

Nine consoles and three handhelds:
http://en.wikipedia.org/wiki/History_of_video_game_consoles_%28second_generation%29

(Granted, only two of the handhelds were programmable.)

EDIT:

A more complete list:  http://en.wikipedia.org/wiki/List_of_video_game_consoles

don't forget about ouya. ..best buy at least has dedicated shelf space for it. and hell, if you want to talk shelf space skylanders and disney infinity might as well be their own platforms as they (each) have more shelf space than wii/wiiU/psp/vita at my local store.

I thought the DS had been discontinued? And Wii, for that matter?