<p>We're usually 1-4 developers / art directors / copywriters on each project at my firm, what methodology would you recommend use to use? Agile? XP? Scrum? Something else? (I know they are all variations of essentially the same concept, yes)</p>

I don't think there's a general answer for it, the question is too broad, and you can't just "adopt a methodology" as if it were a product that you take out of the box, it's something that you evolve over time...but in any case I highly recommend you getting a copy of this book:
Head First Software Development
Then you adapt the ideas you like into your project. Don't worry about names and buzzwords, they will be all "passé" next year anyway.
Keep it simple
at first, adopt the ideas that make more sense and give the most bang for buck, and don't try to solve problems that don't exist yet. It will be a very good start.