Welcome.

First things first: there is still no way to play backup copies of 3DS games on anything. Unless that was a typo and you meant 3D games (for the DS) in which case there is nothing to worry about.
If you don't mind purchasing 2 kits (one for slot-1 and one for slot-2), go with an EZ Flash 3in1 for the GBA games and a SuperCard DSONEi (Mini) for the DS games.
If you want just one card, the SuperCard DSTWO is the way to go - keep in mind, however, that its GBA emulation is not perfect, but most games work pretty well.

(Also, update your PSP! There's like a bajillion new firmwares for it :p)

Hey, thanks for the response!

One particular game I would like to backup and play for 3DS is Mario Kart 7 for the 3DS. I was told/reading that it will play on the a regular DS, just would not have the features obviously of the stereoscopic screen and 3D features. If that is not possible, no big deal, i have my wife's 3DS to play 3D games.

Most of the games I play are time killer type games like the Final Fantasy series, Mario etc.

Is there an up to date compatibility list for the SuperCard DSTWO?

Is there any benefit over getting just the DSTWO vs the two cartridges? I.E. Why buy two cards over one?

I saw that the DSTWO supports SDHC but didn't expand on maximum size. A lot of the cards I've read up on, only support up to 4GB. Found it. Supports UP TO 32GB

About the PSP: I have 5.00m33-6 on it and works for everything i need. What would you suggest on using in place of 5.00?

EDIT: Also, where is the best place to purchase kits? I saw a lot of places that sell them, but also heard of fake kits being sold.

This post has been edited by pyrocide, Tue, May 29th, 2012 at 22:48

lol, where have you read that?

Regarding DS games, the DSTWO is compatible with everything (like most cards nowadays). Should you ever find a game that doesn't work, you'll most likely be able to patch it with the DS-Scene Rom Tool.

Regarding GBA games, most games really work as they should (with the occasional graphical glitch), only very few don't work.

If you get the DSTWO, you won't need to reboot if you want to play a GBA game when you're playing a DS one, or vice versa. If you get two cartridges, you'll get better/near perfect 'emulation' of GBA games on the EZ Flash 3in1 [it's not really emulation because you're playing a GBA game on a GBA cartridge in a GBA console (well, DS, but w/e), but the correct term escapes me right now]. The EZ Flash will also stick out a little on a DS Lite (like any other GBA cartridge), so maybe that's something you don't like. You'll also have more trouble finding a GBA flashkit nowadays, as the GBA is already more than 10 years old. It's just personal preference, really.

Regarding the PSP, the latest stable CFW is 6.XX PRO-B10, this topic has more info on it.

I wouldn't know where to get these because I haven't purchased anything flashcard/kit-related since 2009 or so, but you shouldn't worry too much about fake kits. Just find a shop that's got great prices and buy whatever you want (as long as said shop isn't too shady lol).