Venus conj pluto would tend toward obsessive attraction. The neptune conjunction I would not use at all - neptune moves very slowly and you will have this aspect in common with your entire generation. Venus sextile saturn would tend to give the relationship - "stick-to-it-ness".

Venus/Pluto conjunct  hardcore feelings and can be love or hate...definitely very intense

Venus Saturn sextile

Neptune conjunct Neptune is generational...

But you want to check aspects to Sun/Moon, Mercury/Mercury (can't emphasize this enough), Venus/Mars or Venus/Venus, Moon/Moon... Sun/Moon midpoint is the most powerful one. If you calculate what the midpoint of your Sun/Moon to each other is the very sticky center of a person as it meshes these two vibrant energies and check aspects to *it* in synastry. (Conjunctions and oppositions are the strongest)

Venus-Pluto midpoint in your own chart is the place where you will feel unconditional love coming from you. If your partner aspects it, say for instance, with their Sun... you are hopelessly in love and never to return.  Check your place in theirs and do the house overlays.

Moon/Mars/Venus/or Sun in the 5th/IC or 4th/DC 7th/8th/10th house overlays tend to be very powerful in synastry.

I'd say Moon-Moon, Venus-Moon, Venus-Saturn, Moon-Saturn, Moon-Pluto, Venus-Pluto, and Venus/Moon-True Node.

Oh yes! @ IM: Nodal/vertex contacts too. Woo-wee!!!!

I have my Moon and his Sun on the same degree His Venus is conjunct my moon as well, by 5 degrees.