Skunk, in my honest opinion: BOTH
The Winchester model 94 is a GREAT close quarters weapon. Hits hard and is fast, light and compact. Lighter and more compact (and intuitive) than an SKS paratrooper model even without any frills. The SKS is a good rifle too, especially the Yugo. That's the best buy for the money. An excellent condition used or new model 94 will cost alot more than a shooter grade Yugo SKS, but you'll get a much better and slightly more accurate firearm. The 30-30 is a more powerful round than the 7.62X39mm, but not by a whole lot.
I prefer the Winchester Power Point Plus 150gr. cartridges for hunting and self defense. They push over 2,000 ft/lbs out of the Winchester model 94 barrel. They really pack a wallop close to the power of .308 in a Mini-14 sized gun. The 7.62X39mm ammo I like is Silver Bear 'effect'. This stuff is awesome and I believe it's over 1,400 ft/lbs in energy, maybe even around 1,450 and it's supposed to be military grade as far as I know and it's made in Russia largest ammo plant. Some has a nickel coating of the metal case, but most seems to have zinc coating, spelled as "Zink" on the box, so it's much nicer to your guns internals (especially the extractor) than normal steel cased (like the Wolf crap) and isn't laquered. The nice thing about the model 94 (tactically speaking) is that you can fire and keep it topped off because of the tubular magazine, while with the SKS when you fire ten rounds you're in trouble because you gotta see how fast you can load another ten round stripper clip into the mag in the dark unless you have some loose rounds handy, but then you run the risk (even more so than loading with stripper clips in the dark) of turning your thumb into jello if you manage to release the 'you know what' accidently as you're loading shells. Admittedly, this is not as hard as it sounds with practice, but when SHTF, I would go for the model 94 anytime.
The SKS's trigger really leaves alot to be desired and the AK's (SAR-1) isn't any better unless you invest in a match grade trigger group for the SAR-1 in which case you're above the price of a decent model 94. That said, I still wouldn't mind a nice SAR-1 with some 30 round mags as an "Extra" SHTF rifle. The Yugo SKS is a great value as well. It's had flawless function over 400 rounds and no jams so far. I just sprayed a little Break Free CLP on the rails just to be nice to it. I cleaned the cosmo out really well, but other than that I haven't babied the unissued SKS. I would take any of the rifles mentioned, but would prefer the 94 as a home defense rifle with the edge (but not powerwise) perhaps going to the Yugo SKS (because of its high rate of fire) or Romanian SAR-1 AK clone against multiple home invasion style attackers. Personally though I'd still prefer the model 94 in such a situation because of the benefits mentioned above (intuitive handle, fast handling, light, accurate, keeping the tube mag topped off easily, better trigger, ect.) and the better overall quality of the firearm and ammo.
Good (Silver Bear 'effect' or Cheetah) 7.62X39mm is MUCH MUCH cheaper than the best or even average 30-30 ammo. I pay $14 a box for 20 rounds of 30-30 150gr. Winchester Power Point Plus + shipping and only after I shop around.