Hi Jenna,
If you mean, what would I like to buy next, I would say a Taylor Big Baby. I've played one or two in music shops and have loved them. If you're saying 600 is your budget budget and you're wondering which guitar to buy, then so many factors come into play. Jumping back to the Taylor Big Baby, It's a great instrument to write with. It won't take up a great deal of space, the sound is beautiful and it's very portable. Despite all of the guitars that I have owned down the years, acquiring my first guitar, a second hand Eko Ranger acoustic guitar was the most important acquisition. Firstly, I no longer had to steal my sister's classical guitar when she wasn't in. Secondly, I llost myself in a world of music and songwriting. I can honestly say that I learned to write with an acoustic guitar and I think, I penned some beautiful songs, long before affordable home studios were on my radar. A quality acoustic will serve you well for many years.
Paul