To buy or not to buy.

My birthday is coming up... Fast. In 6 days (Because it's 1:17 in the morning) I'll be 17, which means presents! Yay! 
 
As I was thinking about what to get I compiled a list: 
Rock Band 1 - Game only 
Rock Band 2 bundle 
Black DSi 
Kingdom Heart 358/2 days 
Mario & Luigi: Bowser's Inside story 
New Super Mario Bros  
Xbox LIVE 12 month membership card (Obligatory) 
 
Now, I'm still unsure whether it's a safe bet or not. I used to have a DS (Lite, to be specific), but I ended up selling it to buy something else, I forget what. I definitely want the DSi, but I'm unsure whether it would be a purchase I regret. 
 
The games I picked for it seem solid, except for Mario & Luigi. I love New Super Mario Bros Wii and I love Kingdom Hearts though, so if the decision to get the DSi becomes final, then I'm definitely getting those games. 
 
However, I still want to have some spending money afterwards, just in case I see other things I want to get, whatever those may be. With such an expensive list I decided to ask for 50$, although I would like to have more. 
 
What I ask of you is to help me choose something I won't regret, like getting a DSI just to have it sit and collect dust like my PSP does (Although the loss of my AC adapter does have something to do with it).

Nothing on that list really seems to jump out at me. The DS is great, but if you already had your fill of it before, I don't know if it's worth going back to. Mario Bros DS is NOWHERE NEAR as good as Mario Bros Wii, I love Kingdom Hearts, but 358/2 days is pretty dry and slow going, there's no reason to get Rock Band if you want Rock Band 2... so I guess I would say Rock Band 2, but it depends on how much you like music games. I used to be an enormous fan of music games, but I got burned out and haven't played Rock Band 2 in months.

And as a person who had their DS Lite stolen and replaced it with a DSi, I can tell you there is pretty much nothing about it that makes it better than a Lite. And you can't even play GBA games.

GBA support > DSi store. Go with the DS lite.

You should rock back on the DS/DSi purchase for a while. I guess prices are expected to drop pretty soon because of the 3DS announcement and impending release. I'm waiting until the very last moment to get the DS, because I want to get both a DS (for the GBA functionality) and the DSi at the same time. So I think you could probably look to pick up other things first, and perhaps leave Nintendo's portable stuff on the back burner for a while.
 
As an aside, can the DS Lite play Game Boy and Game Boy Color games? Because as I understand it the GBA could, and since the DS has a GBA port, theoretically... (sorry about the naive question, but I've never had a Nintendo portable system before apart from the Game Boy so I'm not really up with the landscape.)

Get Rez.

Mario and Luigi, I can not even explain how good that game is. It might be my favorite RPG I've ever played.

OK well, after thinking about it I changed the list to: 
Rock Band 1 
Rock Band 2 bundle 
Crimson/Black DS Lite 
Kingdom Hearts 358/2 Days 
The World Ends with You 
(Unknown fighting game) 
 
I want to get rock band 1, but only the game since I've never played Rock Band and I want the songs featured in the first game. Might as well get Rock band 2 with the updated hardware and game. No GBA support is pretty stupid, so I'll go with the DS Lite, plus they have it in my favorite color combination (Black & Red). I'll just continue playing New Super Mario Wii instead, at least until I can try the DS version and I'll see from there. 
 
Also, my friend got a DS herself the other day and she said she got an Acekard 2. I look it up, but I have no idea what it does, other than allow you to put in a Micro SD card. 
 
It's a Hello Kitty DS... Ew.