Clerics are considered to be some of the most powerful classes in the game. Ever hear of CoDzilla? Cleric or Druid-zilla? It says essentially a well-built Cleric or Druid wins D&D. Clerics can buff themselves up to be a better front-liner than the fighter, they can heal, they can blast (especially with anything that comes out of Complete Divine, a.k.a. the book of unadulterated cheese), the only thing they really can't do is skill monkey, unless you play a Cloistered Cleric with the Kobold Domain.