My basic rule for cooking with apples is the shape. If it's round, it's a cooking apple. If it's pointed (more like a tooth) it's an eating apple. Red Delicious is more tooth shaped, Granny Smith are more rounded.
Of course, there are exceptions to every rule but this is a pretty good one for judging varieties you don't know well.
Gravensteins make great applesauce because they just break down like that with very little effort
Honeycrisp are delicious and not very pointed but have a high moisture content which is one of the reasons they don't store well and should be eaten around harvest time. I understand that they also grow quite large if left on their own, bigger than consumers really want.
Opal is one of the newer eating varieties I rather like.