Budget? Lighting, carpet, paint, window coverings.

Actually I think hardwood floors, new mantle, spray paint the fireplace brass thing black, and a new chandelier and you could be set.

oh and get rid of that brown shelfmthing and the vertical blinds

The white walls with the dark trim and beams is very modern. And I think with a great modern piece of art above the fireplace and some more modern furniture and it would look great!

I agree with Truey but for me the deal breaker is the railings. They look Colonial to me and I couldn't handle that.

To move away from the 70s A-Frame appearance, I might consider installing a faux wood plank between the beams in a driftwood color and stain all wood the same driftwood finish. Adding the ceiling tiles could help with insulation and would allow you to run and conceal electric supply for additional ceiling lights.