I don't mean to criticize anyone else's gaming preferences, but here are my own preferences.
I use 1st, 2nd, and 3rd Level Priest spells all the time, no matter what level my characters are. I even let Minsc use his Druid spells. My favorite low level spells are Doom, Armor of Faith, Remove Fear (ever been hit with Horror, Dragon Fear, etc.?), Draw Upon Holy Might, Hold Person, Animate Dead, and Glyph of Warding (the Holy Hand Grenade).
I rarely use spells like Bless, Chant, and Aid when I play BG2, but they came in handy in BG1 when my characters had trouble hitting anything. For that matter, I used all the spells I could in BG1--they're one of the things that weaned me off of my original reliance on ranged weapons in every battle. I guess some people think that Clerics don't do anything but heal the party, but they have offenses and defenses that can put even Fighters at a disadvantage. Fighter/Clerics rock, but only if they use their spells.
BTW, Silence 15' Radius would be a very useful spell if the enemy AI scripts didn't counter it with Vocalize every time you cast it. That's the only reason I don't bother casting it, and it's a shame. Miscast Magic is a nice alternative, but I'm usually too busy to cast it. Holy Word is also a good way to disrupt other spellcasters, and it can be cast almost instaneously, but it's a high level spell.
Anomen should definitely be played as a front-line fighter. But I still take advantage of his spells. I like to buff him up before the battle with Armor of Faith, Draw Upon Holy Might, and Protection from Evil (as well as higher level spells like Righteous Magic--which guarantees maximum damage on every hit--and Blade Barrier and Shield of the Archons, which protects against Dispel Magic as well as offensive spells). I also like to summon a fighting buddy for Anomen with Animate Dead; allies always come in handy, especially skeleton warriors. Harm and Holy/Unholy Word are also worth casting, as well as the occasional Flamestrike. (Ever been hit by a Harm spell? It's scary.)
There are also several protection spells which come in handy, such as Death Ward, Negative Plane Protection, Free Action, Chaotic Commands, etc., and those too can be cast before the battle. There are also spells like True Seeing, which let him see what he's hitting.
Just because it's inconvenient to cast spells in the middle of combat, I don't see that as a reason not to use them at all.
I'd also like to mention that when I'm fighting undead creatures, I let Anomen turn them. Making them explode is cool.
But even if they aren't destroyed, turning them prevents them from attacking you, which is a tremendous benefit. Anomen can then attack them and they won't fight back. At high level, this works even against liches.
BTW, I'm not particularly fond of Anomen (I much prefer characters like Morte in Planescape: Torment, who was performed by the same voice actor), but I have played a Berserker dualled to Cleric and a multi-class Cleric/Ranger before, and that's how I learned most of the information above. But the strategies I used when playing them also apply to Anomen or any other Fighter/Cleric-type of character, including Jaheira, who also rocks if you're patient and focused and take advantage of her abilities.
MoKa, I think you mentioned in another thread that you don't have a manual. That's a shame, because the manual is great place to read spell descriptions. I advise you to find an alternative and learn as much as you can about spells since you want to play with spellcasters like Anomen and Nalia. I congratulate you for making the decision to use spellcasters. I just hope you take advantage of their powers.