Get a card based on the access to internet you have. If you are pretty much constantly in contact with fast wifi 24/7 8GB will be fine as you can just download and delete as you play.

I have 16GB and do this but I could survive with 8GB as I have good wifi and can tether my phone as well.

The PSV original imo isn't very comfy and I can't play it for too long of periods so I would recommend trying the new model and old model(and with cases if possible) to find the one that's most comfy for you

Edit: Oops haha, had this written out last night but just sent now XD

I've had my Vita on Ebay plus a 32G card,  Rayman, and Final Fantasy X for $200. I would have hooked a fellow VgCharter up if I caught this thread soon enough.

Congratualtions!

yeah go with the 32GB , you'll be surprised how fast the memory fills up(still need to stop postponing the 64gb memory card)

Just keep in mind the return period if/when you realize it isn't that great. Experience speaking.

I love mine, is a first generation one. Like everyone else says invest in a 32 gig card, at least.
my recommendations that you didn't mention:
Vita:
Dragon's Crown
Muramasa
Phantom Breaker
Super Stardust

PSP:
Disgaea 2
Dissidia Duodecim
Valkyria Chronicles 2
ZHP
Black Rock Shooter

Oh, and Deception IV: Nightmare Princess, if you like being evil

Lots of very good questions there, but it seems like the answers are about the same. Good choice! I use mine mainly for Danganronpa and P4G as well as a few other games, but it's definitely worth it if you're willing to look and give it a chance. Unfortunately, too few people are

Congrats :) Great handheld. I personally have 3 myself(hoarder complex lol). Such a shame the market never took to it as I love the physical construction, the twin analog sticks(not a gimped nub like the N3DS) the OLED screen, everything.

Is the 8GB memory card enough for it?

If you want PSP and PS game you'll need at least 16GB. Don't forget that some boxed games do receive updates (for example, my physical Senran Kagura Estival Versus is like 2GB big because of the numerous free upgrades). Personnally I've imported a 64GB but I do buy a lot on the Japanese PSN. 

Is the Borderlands 2 port really as bad as people say it is?

From what I heard it's just the frame rate being broken

Is the PSVita fragile enough where a case is required or strongly recommended?

Yes, you do need a pouch or a case, at least to protect the screen when carrying it. I have 3 of them.

Are there any peripherals or accessories that are strongly recommended for it?

Nothing mandatory, but my external battery does help when travelling/commuting.

Is the Vita region locked?

Nope. You can play any game from any part of the planet on any Vita

Lastly, recommend me some games.

I seriously recommend Hatsune Miku Project Diva F & F2nd of you like rythm games. Persona 4 Dancing is also good or so I hear. Lost Dimension is coming soon at it's an original and pretty dense RPG. Also the Atelier games if you've never played them. Grim Fandango is a masterpiece of puzzle/point & click game. Lastly, Dengeki Fighting is coming soon and it's a good 2D fighting game.  

Thank you Vita owners of VGChartz, you guys sold me a vita :]

I did well I'm truly glad to have been of help

I got the honor of receiving a PS4 review copy of this one after having never played a Deception game before. All I can say is thank goodness other people can try a demo and aren't obligated to finish the game.