Well, after some more tests, seems now I cant even get it to run with Forge!
I load it up, no mods, no forge installed.
I drag forge's contents in minecraft.jar (ignoring meta-inf, not deleting as I heard forge lets you keep it),
I get a crash report in multimc, but it doesn't show up in minecraft.
I then delete the meta inf, thinking maybe its somehow breaking it anyway,
then I re-insert the forge meta-inf. It still crashes.
I did this again with forge 6.6.2.534.