Japan --- black , white , pink , lime green , metallic blue , glossy red
North America --- black , white , pink , light blue
Europe --- black , white , light blue , metallic blue , glossy red
Australasia --- black , white , pink , metallic blue

The DSi is currently available in seven colors; only the matte black and white models are available in all regions. The lime green color is only available in Japan,and pink is available in Japan, North America and Australasia.The metallic blue color is available in Australasia, Japan and Europe.European countries also received light blue and red on October 23, 2009.
There are numerous special edition models available, including the Ace Attorney Investigations: Miles Edgeworth and Final Fantasy Crystal Chronicles: Echoes of Time models and more !

Similarities:
-ALL the DSI can play DS games (no region locked)
-ALL the DSI can connect and play multiplayer wirelessly
-ALL the DSI is the same except the difference written below.

Difference:
-DSI shop is region locked(it means that a Japan DSI can only connect to Japan DSI shop,Europe DSI can only connect to Europe DSI shop.)So there is only 4 different DSI shop existed all with different downloadable content.
-DSIWARE games released are different by region(eg.if megaman 10 is released in JAPAN DSI shop,there is no way other region DSI can get this game until this game is released in their respective DSI shop.)

-Region DSI is different in language.(Japan DSI all in japanese,Europe DSI available in 5 europe main language,NA DSI available in english,spanish,french)

-DSIWARE games downloaded from DSI shop is different in language as well.(DSIWARE GAMES in japan DSI are all in japanese,NA DSIWARE games are all in english.)

WHAT I COMMENT ABOVE IS ONLY FOR DSI not DS lite.THANKS.

In malaysia,most of the retail shop sell North America or Japan version DSI.Europe and Australasia version is hard to get in malaysia.(maybe bcoz the price is expensive?)
For u guys who wanna get DSI,i recommend u get the North America(US)
DSI bcoz:
-we have brazil hack to buy dsiware games
-all dsiware games are in english

You can get the Japan DSI if u:
-can read japanese
-know what type of credit card works in malaysia to purchase dsiware games
-love the japan DSI model color so much.(lime green,glossy red, metallic blue,limited edition)
-wanna to get some japan only released dsiware games
-make no mistake,japan DSI shop got way more games than US DSI shop.(but all in japanese language)
To differentiate japan,NA,europe,australasia DSI,please refer to the DSI boxart.
THANKS EVERYONE !!! ENJOY 

Good answers. Thanks a lot. I've search all over the google but they nvr specify the languages for each DSi region.

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Added on November 19, 2009, 12:16 am
Good recommendation. Thanks man.
Cause I really headache for days on which DSi to get for my gf. She told me that she likes red and light blue. I quite like the red. Unfortunately it's not available for the US DSi. Guess I'm going for the light blue, no choice. =\
Actually white color not bad also but I already have bad experience with my white psp, so fast the console gets dirty

hmm still searching for someone to bring in US nintendo card.

virtual console is for Wii