Need opinions on future gpu's

Ok so i hope im posting in the correct area, if not oh well. 

Anyway i dont really need help building pc's as ive built a bunch of gaming pcs for myself and friends without problems. But i need peoples opinions on a few things. 

My mothers in the market for a new pc since her old hp is beginning to become sluggish. I feel like upgrading anything in it would be a waste, and since i planned on making a new pc she can wait out another half year or so to get my current one. 

I planned on waiting for skylake to release before i make my purchases. correct me if im wrong but broadwell and skylake are going to use the same microarchitecture? I know there arent any benchmarks out for skylake but you think it would be worth the wait? Also id like to wait for 800 series gtx cards and ddr4 to release which i believe is around the corner.

Right now i looked into either a gtx 770 4gb twin frozr sli or 780 3gb gtx sli. From what ive seen frame rates arent too different and im not sure if the extra 200 dollars would be worth sli 780s and two less gbs of ram. 

Sorry for the great wall of text but id appreciate the opinions on these gpus/cpus.

skylake will be the next intel tok, probably on a new socket again socket 1151, so that means diffrent platform.

About the gpu´s, im personaly not realy a big fan of dual gpu setups in the first place, because they use more power, and the scaling is not allways ideal, Offcourse if you play games that are godd optimized for sli, it would be great to sli 2 GTX770´s or 2 GTX780´s, but there are also alot of gmes, that don´t work that well. so yeah im personaly more a fan of a highend single GPU setup.

GTX770 4GB, is a bit of a waste in my opinnion, offcourse its a great card, but in my opinnion the 770 is not powerfull enough to utilize 4GB of ram. i would personaly pickup a GTX780 or R9-290 then.

Offcourse if you could afford a GTX780Ti would be nice. this is the fastest single gpu on the market right now. But yeah who knows what happens over 6 months? maybe the GTX8xx series allready out by then?

Also skylake does not come this year. intel works 2 years on one platform, with one cpu + chipset upgrade, after a year tik so i dont expect anything on skylake earlier then june 2k15 or maybe even 2k16.

Thank you very much for the reply. Yeah sorry i mixed it up. Broadwell is on the same platform as haswell. Skylake completely new platform youre right. Yeah i know skylake doesnt come this year but later in 2015 possibly 2016 becuase of the delay on broadwell :(

I planned on playing games at 2560 x 1440 which is why i was considering sli. But im not sure if i could afford a gtx 780ti as of yet. but i doubt id sli further down the line with such a powerful card which is why i was considering going sli since i can probably get it for a bit cheaper than a single 780 ti and have really good performance. power also isnt too much of an issue for me. ive also always preferred a single gpu, but decided id give sli a shot.