Having owned all 3, and the vita being the only one I ever sold back, I'd say the 3ds and wiiu are the wisest of investments from a mainly pc gamer point of view.
I'll throw out there, I'm biased towards nintendo games, but I greatly enjoy them. I picked up mario kart 8, party, and golf for my 3ds and wiiu and enjoy them in my downtime between work. I can't bring myself to justify dumping money into the more expensive ps4 and xbox one of this gen either if most games will still have the optimal experience on my pc.
The vita is interesting though, I dumped about 100 hours into P4G and Project Diva F, but everytime I visit my local game shop I can't help but notice that the majority of the stock hasn't changed since I had the vita over a year ago. I did like the console itself however, it just fell behind my 3ds even when it came down to jrpg releases, which is what I mainly use handhelds for.
Tsujoi wrote...
I would go for a 2DS, simply because I never use the 3D function on the 3DS I own.
A used 3ds xl is by far a much better investment. It's only about $50 more than a new 2ds, and has much better build quality, a bigger screen, and something that can actually fit in your pocket.