Re: Strings 4 a Acoustic, please.
Strings make a huge difference on a guitars tone... especially an acoustic. Ultimately you should try all kinds of strings to find exactly the feel and tone you're looking for. It's a long process but it's well worth it.
The first thing you should do is choose what gauge you're comfortable with and what compliments your playing style. If you're just going to be strumming away for rhythm I would suggest a heavier gauge to give a fuller/louder tone. If you're gonna bend the crap out of those strings then go lighter. Some guitar manufacturers actually suggest you don't go outside a certain range (11 to 13, for instance) based on the type of guitar you have (dreadnought, jumbo, grand auditorium, etc.)
Now you can focus on the type of strings you want (phosphur bronze, steel, wound, unwound, wrapped (Elixir), etc...) All of these have different tonal characteristics and need to be heard with an UNBIASED ear.
Another huge difference in tone is the cleanliness of the strings. The major advantage of the Elixir type strings is that the wrapping prevents the steel from rusting/oxidizing which causes strings to loose their brightness and articulation.
For what it's worth... my Taylor 414ce came with Elixir's (12s) and I was HUGELY skeptical about them. I always heard negative things about poor tone but I don't agree with that anymore. My first set lasted about 6 months and were just as bright as they were the 1st day I played them! In fact the only reason I replaced them was because I was getting a free setup from the dealer I bought it from. I have a beat-up pawn shop Fender Dreadnought that I string Martin Phosphor Bronze (12s) with and it sounds very full. I have to regularly clean them with FastFret to keep them bright.
Good luck!