Just bought a 3DS XL. What do I need to know/own?

I've been posting a bit on the Daily threads talking the 3DS after I saw a preowned one cheap then deciding whether to get it or not and then wondering about the XL. I think I've been posting a little too much about it on the Daily thread so I though I'd make a thread for it. I bought an XL on eBay yesterday and I should have it either tomorrow or the day after.

It comes with the following games:

Pokémon Black 2 (boxed)

Dragon Quest IX (boxed)

Pokemon Dream Radar (downloaded)

Planet Crashers (downloaded)

Undead Storm (downloaded)

and the following accessories:

Charger (including since it doesn't come with a new XL)

Carrying case (can carry console, games, spare stylus and accessories)

4Gb SD card (I think all new XLs come with this but I'm not sure)

I'm looking forward to getting this but I'm wondering what must have titles there are I have to pick up and if there's any real benefit to buying an XL new rather than preowned. I know you can register the XL yourself if it's new but I don't know if that brings any benefits or not.

If there are then I could easily sell this XL along with everything aside from the 2 boxed games and make nearly what I paid for it back and then buy a new Mario 3D Land XL with the money (the games and accessories were why I went preowned) meaning I'd effectively have got 2 boxed games cheap but I'd only do this if it's worth it.

The most important thing I'm looking for though is game suggestions. I've got the following on my wish list:

New Super Mario Bros. 2

Super Mario 3D Land

Ocarina of Time 3D

Donkey Kong Returns

Luigi's Mansion: Dark Moon

Pokémon X/Y

Mario & Luigi: Dream Team

Fire Emblem: Awakening - not 100% on this since I've never played an FE game before but it sounds good

Most of these are unreleased and I don't really know what great games have been released for the console so it's not a long list. I don't know what's on the e-shop that's worth getting and there's still some great DS games I've not played since I've not touched it in a long time.

I'd really appreciate some suggestions as that's me finally getting back into Nintendo gaming. Also if there's anything I should know about when it comes to the 3DS then I'd appreciate that as well.