Dear FibulaThe best cases available (IMHO) are Calton cases (very expensive indeed and a bit heavy but superb protection and quality - I use one for my mandolin) and Hiscox Lightflight cases (a moulded, strong and light case - I have one for my best guitar). The latter are not too expensive and, in my view are much better than the "traditional" covered fibreboard type case. Both are UK-made but are available from good acoustic instrument shops worldwide. Hiscox cases are supplied as standard with a number of luthier-made guitars and are quite similar to the original cases supplied with Martin and a number of other top US manufacturers.
If price is a limiting factor and you get a fiberboard type case, a slightly "domed" one will afford better protection to your guitar. Again, most good instrument shops should have a good selection.
Do take your guitar along and make sure it is a good fit in the case. If minor adjustments are necessary, it is usually possible to make a little extra padding with some foam and velvety-type material to match the original.
Do get the best case you can afford, it will protect your instrument from disasters that WILL happen if you take it out and about (talking with some 35 years experience here!)
Hope this helps a little,
mcmoo