I dont think I've ever, ever, ever, ever played a game that was NOT buggy. Ever.
Open-world games are at times hard to be rid of glitches and bugs, they just have so many variables.
I've played New vegas, and there were'nt any bugs that broke the game, and I didn't even update it.
Maybe your Xbox is just misfunctioning? I've never had friends have big problems with NV