Generally: Int, Con, Dex, Str, Cha, Wis
Yes, you can safely dump Wisdom. You get a high Will save anyway, and unlike the Barbarian, who can wipe out the party if confused, dominated or otherwise ensorcelled, you’re usually surrounded by party members who can simply grapple you to put you out of the fight.
Why Charisma? Frankly, since you get extra languages from high Int and possibly ranks in Linguistics, you MAY consider actually being able to talk to things once in awhile…
Why not dump Strength harder? Frankly, it’s because I like to carry stuff, and some DMs are encumbrance nazis. It’s really hard to carry interesting things when you have a strength penalty, especially before you get magical aid, such as bags of holding. I also hate the idea that one character ends up carrying all the utility gear, and if something happens to that character, the rest of the party is lacking essential gear.
Why Con over Dex? Yes, Dex is nice in the early levels, where you might care about the Dex bonus to AC and the bonus to ranged attacks. However, you’re going to rely on luck to get through those early levels anyway, and later on, the only thing that keeps you alive is a decent pool of hit points, because things either hit you with things AC doesn’t help you with, or you cast spells to make sure they can’t hit you.
Four Types of Wizards
Debuffer / Enchanter
You want Intelligence as high as you can make it, dumping any other stat if necessary. Your usefulness relies almost entirely on making enemies fail their saves against your spells. Because of this, you want spells that affect multiple enemies, hoping that some of them will fail their saves. You also want Spell Focus, or any other feats/items that make it harder to save against your spells.
Frankly, you should be playing an archer instead, or at least a Sorcerer. You want a higher Dex if you can manage it, mostly because you’ll be relying on some ranged touch spells, such as rays. It’s also worth knowing that you can take Weapon Focus: Rays.
You don’t really need caster-stats, as things aren’t going to be resisting your spells, so you can pretty much go for flavour: high Int if you want to specialize in Knowledge, or you can even go Charisma and be a party-face in a pinch – just remember that without high Int, your skill points are severely limited.
Many guides have been written extoling the virtues of the Conjurer, and I will agree that they are great. DMs MAY require you to converse with some of your summons, so high Int and Linguistics is a must, and you may even need Animal Handling, Ride or a decent Charisma.