Mikey is a great guy, and Eastmans are seriously good, but are often way over your budget, even used:
http://www.guitarcenter.com/Eastman/Guitars.gc
Right now, you've tried a BMW after driving around a rusted out Toyota, and sure, it's OMG. Just like cars, there are a lot more guitars between the two levels. Aside, most will not come with a case, but it is wise to get one. So I recommend checking out what's available at around $400.
Musician's Friend/Guitar Center websites have a useful sort-select feature, so here's a quick look at $300-500 for 6 string acoustics:
http://www.guitarcenter.com/6-String-Acoustic-Guitars.gc#pageName=subcategory-page&N=18154+1086&Nao=0&recsPerPage=20&v=g&postalCode=68113&radius=100&profileCountryCode=US&profileCurrencyCode=USD
This is the same company for Guitar Center stores, where you should go and try many, as you have exactly enough experience to do that. There, I would further recommend skipping Fenders, and trying Taylor, Seagull, and others, but don't get seduced by the "cheap" Martins.
With luck, you'll get a really nice guitar that you can use for many years. If, like many, you later shift to electrics, don't sell it then, either, or you will regret it, believe me.
Hope that helps.