Yes paying monthly can raise your credit score incrementally. A few months ago I had $17k spread out over 3 credit cards roughly as such: Card 1 $12k, Card 2 $3k, Card 3 $2k. I paid off Card 3, the lowest balance, and saw an immediate jump of 41 points. The jump was from the 660's to just above 700. I have since paid off Card 2 and am waiting until the end of this month for the zero balance on that card to be reflected on my credit reports. I assume I will have another jump but wont really know if and how much until it hits.
Card 1 is also down to about $10.5k now so that should also help. Overall my Utilization rate has done way down and that is what changes your score I believe.
I was a bit ticked when I checked my credit score out of the blue a few months back (after years of not paying attention) and realized that my score was not in the mid 700's or higher. It all had to do with credit card utilization rates. I have great credit otherwise. I, like you, charged my new toys (HD TV, Surround sound system, etc.)
It is comforting to know that my credit is going back up with my payments to the cards.
I think the poster above me is correct in saying get a loan instead of charging it. Lesson learned.