Magi vs. Vampires

In general, the power of Magi and Vampires work perfectly well on each other.  There are several specific issues, however:

Arete vs. Generation

The following table can be used to compare Arete and Generation as needed for determining how and if certain things work.
 
 

Arete Generation
Oracle 1
Oracle 2
10 3
9 4
8 5
7 6
6 7
5 8
4 9
3 10
2 11
1 12
Sorceror 13
Sleeper 14
Sleeper 15

Auspex vs. Arcane:

Arcane only works against Vampires who possess Auspex if the amount of Arcane is greater than the amount of Auspex they possess.

Auspex vs. Magickal Illusions:

A Magus must have Mind higher than the Vampire's Auspex to successfully use mental illusions on an Auspex-possessing Vampire.  If the Mage and Vampire have equal amounts of Auspex and Mind, the Vampire gets a Perception + Occult roll vs. the Mage's Subterfuge + Occult to see if he realizes he's dealing with an illusion.  The Vampire also gets the normal Willpower resistance to Mind magics if that fails or if he had too little Auspex to resist in the first place.

Can I break Blood Bonds with Mind and Spirit?

To quote Blood Treachery, "Can you get more successes than God?".  No, you can't.  A Blood Bonded person cannot be made to hurt their regnant with Mind magics.  This doesn't necessarily stopping you using Mind magic on them to make them charge into some Sabbat base armed with a pocket knife, but...
 

Can I make synthetic Vampire Blood?

The answer is yes and no.  You can enchant blood to have some of the properties of vampire blood.  However, you're not God, and can't convey the full package (although if you're an Archmage, you could come pretty close).  And anything you make is dynamic magic, and thus subject to paradox.  About the closest you could come would be to find a vampire, tie him down, and use his body as a processing plant for magically created mundane blood.  This is a great way to make lots and lots of tass, but also a great way to end up in deep trouble the next time you have a paradox backlash and he gets possessed by some Paradox spirit and comes after you...
 

Dominate:

It is difficult to use Mind magic to force Vampires to do things.  This difficulty rises with the generation of the Vampire.  A mage trying to use Mind 4 or 5 to control a Vampire's thoughts or even to reprogram him must have an Arete equal to or superior to the Generation of the Vampire.  (See the Arete vs. Generation table).  Conversely, Dominate fails against Magi if the Vampire's generation is lower than the Mage's Arete.  (Thus, a 6th gen could dominate Magi with an Arete of 7 or less).

Magick vs. Thaumaturgy:

As noted in the Blood Treachery book, Hermetics and Tremere can counter-magic each other's powers in this area.  The same applies to Verbena, due to their knowledge of Blood Magics.  Also, Hermetic magic counts as coincidental inside Tremere Chantries.  This makes for rather UGLY fights.

Thaumaturgical Wards:
Thaumaturgical wards can be sensed and unravelled with the use of Correspondence plus the appropriate spheres.

Matter vs. Protean or Vicissitude:

Vampires, being dead, count as 'Matter' for determining sphere effects.  Vampires with Protean or Vicissitude can roll their Discipline to resist Matter effects.  Being turned into furniture will not prevent them using their powers on themselves.  (A Vamp with Protean 4 could spend a blood point and turn from a desk into a wolf.)  Other Vampires are out of luck.  However, Vampires, due to their curse, tend to revert to their base form, the form they had at the Embrace, with each sunset.  This is harder to do when the vampire is, say, a lawn chair.  Basically, the effect will gradually unravel, losing one success each time the sun sets.  Once enough successes decay away to undo the effect, the Vampire reverts to normal.

Matter can be used to fix Vampires who have been messed up by Vicissitude.

Mind vs. Chimerstry and Obfuscate:

A Magus with Mind is still affected by Obfuscate higher than his rating in Mind.  If both ratings are equal, the Obfuscater can roll Subterfuge + Occult vs. the Perception + Occult of the Mage to try to keep him from seeing through it.  The same applies to Chimerstry.

Mind vs. Presence:

Any mage with Mind magic will notice the use of Presence before it affects him on a successful Perception + Awareness check at a difficulty of 6, if it gets equal or more successes than the Vampire gets with the power he is using.  Should he notice it, he then can attempt countermagic with Mind (although given the Vampire will probably heavily outweigh him in the # of dice used, he may well be out of luck).  Mind magic can be used to undo Presence effects, and as with anyone, Mages can spend Willpower and make a willpower roll to overcome the effect for a round.
 

Life vs. Vicissitude:

Life can be used to countermagic the use of Vicissitude on living things.  Also useful for going in and undoing the effects (It generally takes Life 4 or 5 to go in and fix the damage afterwards, or Life 3 for the Magus to fix damage done to himself).

Vampire Blood as Tass:

Vampire Blood functions as Tass, each blood point containing a point of Quintessence.  It also tends to be stinky with Entropic Resonance.  Let users beware.  And keep in mind that frequent Vampire hunting will tend to get Vampires to start hunting you.

What Spheres effect Vampire Blood?

Spells which affect Vampire Blood need to incorporate Life and Prime, generally.