James, not biggie. I started to make it a thread for both PF and 3.5 but decided to narrow it for the same of confining the parameters just a bit
In particular I was looking at Assassin options without being Full Caster. As pointed out the best are probably those that can kill without even having to show up to the murder.
I was looking more for a discussion of the merits of Bard, Magus, Inquisitor, and yes the nifty Vivisectionist sorts as good Assassins that tend to be boots on the ground and do then kill themselves.
Basics: Each of these classes have the same base 3/4 BAB, 2 Good Save chassis and they all have good to great Skill options. In the case of the Magus that is mostly because of being Int base.
Social Skills Bards certainly come out ahead here probably with Inquisitor then Magus. Bards have the skills and the Cha support. Inquisitors have the skills but probably not the Cha support. The Magus doesn't have the skills and probably dumped Cha to boot. Smooth, a magus based Assassin probably is not
Spell Lists: Bard's and Inquisitors both bring spells lists loaded with Assassiny helpful awesomeness to the party but they have the problem of having limited spells known.
These two spell lists are weighted with definitely different focuses but one of the biggest things that jumps out to me is the Bards greater number of mobility and travel related spells that would help with bugging out. The Inquisitor brings some big dogs that the Bard does not though like Nondetection and it also brings more offensive and defensive buffs.
The Magus brings loads of utility for purposes of getting in and out of a job from Expeditious Retreat, Invisibility, and gaseous form, to big dogs like Teleport. Their list also contains plenty of sledge hammers too as you might imagine. Perhaps the most important thing for a Magus Assassin is that they are not limited by Spells known. They can learn their spells and prep as needed for each job. I think a big hit on the magus list as compared to the Bard and Inquisitor is that lack of means to deal with and thwart Divinations or to charm/modify memories.
The Alchemist has a pretty rockin list of Formulae (spells) for an assassin. I'd not really looked it it much before. Loads of buffs, Invisibility, Fly, Gaseous Form, Nondetection, transmutations (polymorphs), and much more. They have lots of mobility and transportation enhancing options including short range teleports. For long range escape travel though they are locked into polymophed travel options, flight, or Shadow Walking. The alchemist doesn't have much in the way of Make Nice (charm) but definately has some interesting and probably useful compulsions and such like Magic Jar
On looking I think they may have the best cross section of Assassin enabling goodies in their spell list, particularly for those not looking for a social focus. Plus, they are not limited by Spells Known which I think is a huge boon.
Summation of some of my crazy random ponderings:I think that each of the above could make effective Assassin themed characters. Bards, certainly lend themselves more to the social intrigue on one end of the spectrum while Magus I think are going to be more Smack down oriented sledgehammer style Assassin. Go figure right? I think that the Inquisitor is somewhere between the Bard and Magus stylistically. That is not to say that an Inquisitor can not bring the Smack. I know they can, but their spike damage is not likely to be anything compared to what the Magus brings to bear.
For what I'm looking for though I think I may have found a winner in the Alchemist, a place I was not even looking towards as part of the discussion (thanks Linklord). In particular the Vivisectionist I think will rock in this role. They can sneak in (magically enhanced or not), kill by steel or by poison, and get the heck out of dodge all while having the means to thwart most magics that could be problematic. The Alchemist just may have the best balance of tools for the job.