I prefer to use my readers sans case, but put it in a case when not reading. Since Best Buy only had one 350 and no accessories last week, I had to scrounge for a case. Luckily, I had just bought a Sony Clutch case for my Opus, and it works just as well for the 350. Sony advertises that it works for the 300 AND the 600, so it should also fit the 650.
Link:
Sony Reader PRSA-CC/W at Sony Style US
It is out of stock in the US. But I've noticed it's on clearance at lots of other web retailers. I bought mine on eBay from TigerDirect.
The stock photos don't do a clear job of showing two of the nicer features -
+ it is incredibly well reinforced and stiff, giving great protection
+ a soft feltish flap covers the opening with the magnetic flap, so none of the device is exposed, which is great for putting in a purse/bag.
My only complaints are:
- the faux leather is very real looking, but since it is white, it will get dingy quickly
- the felt/suede lining leaves fuzz on the touchscreen
I'm hoping it stops shedding soon.