Oh, ah... The reason they're excited about a VHS player is because of old movies that aren't out yet on DVD or BluRay! And they don't care about Blu Ray because, um, visual quality isn't important, it's all about the story? Yeah, that's the ticket... No technological advancement inconsistencies here...
Fortunately, 64" remains a big a screen size. Unfortunately, the fact that she specifies widescreen totally dates this comic (unlike VHS, which, as we've established, is totally reasonable to mention and doesn't date anything whatsoever).
This is very non-Elliot behavior. Sort of, anyway. After eating lunch with Susan several times by this point and getting to know her better, so inviting Susan to hang out wouldn't be that strange. Ellen's history with Susan doesn't include that, however, and Ellen barely knows Susan, so this remains very non-Elliot behavior.
In any case, if Susan being a main character wasn't certain before, then THIS--*THWACK* OW! Okay, okay. I'll stop making labeling tons of different moments as the moment when Susan became a main character. She totally is one. Happy?
Commentary added for December 31, 2014