For those interested in pyromancy, my personal favourites:
(1) Fire Orb -- if you can afford this, it's much better than Fireball. I carry 2x and use it to do most of my medium range combat.
(2) Great Fireball -- see above, but with more oomph -- when extra crispy is what you need... less uses, bigger projectile, more damage.
(3) Iron Flesh -- someone else covered this -- if I didn't have this and the 2 other spells, I never would've taken out the Anor Londo boss(es) on my own.
I've never used combustion/great combustion much, they're a bit closer range, which I'm okay with using straight melee for. The sweat one for reducing fire damage was good against the first boss in Demon Ruins. Firestorm is kind of fun, but it's unpredictable, so I don't use it that much. My new favorite is Fire Surge (found in painted world of aramais); it's basically a flamethrower -- works great for dealing with opponents when you're circling each other -- then when they stop to heal, you pop em with fire orb or great fireball.
Fireball isn't a bad jumping off point if you can't afford fire orb.
Beyond that, I have almost all the pyromancies, but I mainly stick to the three listed above.
