Banishment

Abjuration
Level: Clr 6, Sor/Wiz 7
Components: V, S, F
Casting Time: 1 standard action
Range: Close (25 ft. + 5 ft./2 levels)
Targets: One or more extraplanar creatures, no two of which can be more than 30 ft. apart
Duration: Instantaneous
Saving Throw: Will negates
Spell Resistance: Yes
Description

Other Information
Minimum caster level is 11th for Clerics (22 HD affected) or 13th for Wizards (26 HD affected) or 14th for Sorcerers (28 HD affected).

Pros:

Can affect multiple targets.

Can improve SR caster level check and Will save DC with objects the target dislikes.

Cons:

Can only be used by standard players on the Material plane.

Tricks/Combos:

Knowing what a target dislikes can be very helpful, since you can then present appropriate objects to make it harder for it to resist the spell. Any damage reduction weaknesses qualify as hated objects, as could other items at the DM's discretion. For example, a classic mythological vampire (NOT a D&D vampire) would hate garlic, the cross, holy water, a torch (representing sunlight), wooden stakes, etc.

Overall:
A good spell in the right situations. Affects a large number of HD, and can be very difficult to resist if you have a few of the right objects handy. However, it's utterly and completely useless against non-extraplanar beings, so it's most useful as a "use when needed" spell (Sorcerers or scroll) or when you know you will be up against extraplanar creatures.

Recommended for Clerics?
Situational. Don't memorize it regularly, but remember that it's there.

Recommended for Sorcerers?
Yes. Although it's not an optimal use of a spell slot since you won't use it regularly, it's a good idea to have a spell or two for dealing with specific situations such as extraplanar beings. Take either this or Dismissal, but only one or the other. (I would personally take Banishment, due to the hated items feature. If you need to, try to use scrolls of Dismissal until you're high enough level to get Banishment.)

Recommended for Wizards as an initial spell choice?
No, it's too specific. You should already have Dismissal, and you can make do with it until you get a chance to scroll-scribe Banishment.

Recommended as a scroll?
Yes. If you didn't learn Banishment, or if you had to memorize other spells, Banishment is a good one-shot spell that can immediately end a difficult battle.