RE: do you really need a computer radio????
No, you don't need one! I flew the first twenty years without one. However, now that I have one, I wouldn't buy one that wasn't! They're just plain nice and have features I find very useful and choose not to be without.
For starting out, buy what you can afford. If you can afford a computer radio, why not go for it? However, what's more important is to be compatable with whatever buddy system you link up with.