I use Dark Blast throughout the whole game because you can spam it no matter what The only other magic I have used is Dark Lance for more direct shots, and when I use that, I usually have a Magic Drop used, to boost the power.
As for the weapon, I just use what you feel comfortable with, and upgrade that. Once you beat the game once, you will be so strong it won't matter what weapon you have, you will kill most things quickly.
The best weapon in terms of raw damage right of the bat is the Phoenix Spear. It can be bought in the desert city (forgot name) during the second half of the game. Not too sure about full upgraded though
My favorite Spells apart from the two mandatory ones (Blast and Lance) are Dark Hand and Dark Execution. Hand, because it hits where the camera is pointing so you can use it from any angle and Execution because it has decent damage, range and MP-Usage.
But since the game is extremely easy on normal anyway, there´s no strategy involved anyway.
My favorite Sword would be the Beastbain 1h-Sword. You get it right at the beginning and can use it throughout the game...seems to be the best 1h-Sword at least the best I´ve found in my 1st playthrough.
How much is the phoenix spear? I just started and was thinking about grinding out some money for various weapons and was curious if i really wanna spend that much time killing sheep for mutton(seems like the best way to get money early on. I just went to the aerie for the first time so I'm pretty early on).