Cleric is an incredibly versatile class, but no one cleric has the feats and stat points to do everything a cleric can do.
Pick something you like and go with it. A cleric can be a tank, a party buffer, a healer, a blaster, a utility caster, anything, but it can probably only do one or two of them well.
When you pick your pclasses (if any) do it with an eye toward reinforcing the role you've chosen. It's not 100% true that you have to avoid non-spellcasting levels. It's just mostly true. Sometimes what you get is worth what you give up, especially if you're only losing one level in a 20 level progression.
Whatever your chosen role, it is important to remember that you have versatility, and to use it when the situation calls for it. You're a lot like a wizard in that respect - if you know what's coming, you can prep a really devestating set of spells. Your primary role is just like the wizard's standard spell selection. It's what you expect to do most of the time, and what you're really optimized to do, but it's not the only trick you've got.