Hello

I am wanting to purchase a couple of digital recording devices.
1. Camera
2. Sound recorder
I want the digital optic recorder for the sake or performing and teaching, but I really have no idea where to start. Does memory and things like this matter ? I suspect it does (but that's as far as I get with that).
Also, I currently have a little minidisc recorder that is getting old and worn out. It is not working as well as it used to and I am pretty sure there are better things on the market these days. A friend of mine was telling me about a digital recording device that I don't think even uses discs... but I can't seem to remember the name of the device... has anybody heard of anything like this ?
Any suggestions and recommendations are appreciated.
Thanks,
m1469