Using just Arch-Mage robe's, Saren Avaro*'s amulet, and Marecki's mask, I have a recharge rate of 225%, +100 Magicka, and 15% reduction in cost of all spells.
Considering I use my boots and gloves for sneak and one-handed attack skills, I think this is pretty good for a char who isn't 100% dedicated to Magic. I'd love to find Thalmor boots and gloves that are enchanted, they look awesome.
What boosts do you have? What clothing/armor do you use for your mage or hybrid mage?