Cleric is my favorite class both in 3e and 2e, and here is why: You are the one who keeps the party alive through your unmatched healing abilities (and sometimes the only healing abilities). Then you have some great defensive spells and a few offensive spells to mix things up. So spell wise you are mostly support with an offensive spell here or there. However, unlike other spell casters you can dive right into combat. Your weapon selection and fighting skills are fairly good, and you have enough hit points to take a licking. Even better, you can wear ANY armor without penalty to your magic, so you can fend off blows as well as any fighter or paladin on the block.
Now about your character specifically. You are going to probably choose between Pelor and Heironeous as your patron deity based on what you specified. if you want to go the more combat oriented approach go with heironeous, take war and law domains so you can use a longsword. If you do go this way, you need to pay attention to rping a LG cleric. This means you are going to be helping anyone you can, and being a good deal like a paladin, except not as strict. This is my favorite type of cleric, and I usually like to focus on defending justice, but it is a more difficult type because you have lots of moral obligations (which can be great in some ways). As for skills you MUST take large doses of concentration as you will be casting lots of spells with badies all around you. Healing is good at lower levels, but loses much of its potency when you start casting heal. Still I would take it if you want to care for the sick or injured unless you don't want to focus on healing others. Knowedge religion can come in handy so a few ranks there over time is usefull. Diplomacy is a cleric skill I like to get. Clerics often end up the negotiators and party representatives because they are usually respected by all good people, plus they often have good Cha scores. Feats I like are combat casting, power attack, improved initiative and extra turning, I am not a big brew potion fan for clerics but that doesn't mean they don't go well together, mostly it is my personal preference.
My last suggestion is to take up the party leadership if you can and if you feel capable of it. You are the character most likely to have good charisma. Also, not many people will respond well to the barbarian in conversation, the rogue may not be trusted much by others, and common folk tend to distrust mages. However, as I stated before, everyone usually likes clerics, the care for the poor, heal the sick, have the wisdom to speak with sages, can be trusted by merchants to be honest, by innkeepers to not cause trouble, and command at least some respect from the nobility. As a cleric you have great responsibilites, but in my opinion the cleric is a great and fun class to play from all angles.
