High res for fire and electrics is always handy. Its there main attack. Use freeze it makes it alot easier.
Totally agree. The first time I played through (haven't got that far on the second go yet) I simply cast Freeze on the Dragonrider. Being prepared before I went in the room (it's my staple spell) I got it off before it took an attack against me - and it never got another chance. Set to work with a big sword on an immobole foe; end result, dead dragonrider. I'd got Freeze maxed out by this stage, but it really made what was supposed to be one of the toughest fights into basically one of the easiest.