Im going to be picking up AC3 for the PC next month but I want to pick up Liberation for the Vita tomorrow. My question is, would I need to complete AC3 to get the most out of Liberation?

This is a good question I have the same plan as well.

I assume both stories take place cocurrently just in different cities and I doubt the endings of either game will affect the other story in any significant way.

As far as I've heard, you can basically play them in whatever order you want. So that means I'll be playing ACIII whenever I can, and make my way through Liberation when I don't have access to the TV.

Don't really need to play them in any order. Both were made to be self-contain stories with possible referencing.

@ValiantGrizzly: That is also my plan.

I remember hearing that Connor appears in Liberation but I don't know any more than that. I think the best bet is to play through 3 first. It's the next main installment and liberation is just a side story that will probably expand on areas of 3's story I'd imagine.