Hi Ivano,
First, by particles, did you have something like this in mind?
Simulate Thousands of Particles in Real Time
Second, that is quite an ambitious list of things to accomplish from the perspective of art ( or anything else for that matter ). Let me followup with another question/suggestion: what of that list do you have as your most immediate interest? If you had to give a friend an example of your art within a short amount of time, what would it be?
Additionally, since generative art seems to be developing as a hot topic, have you looked at systems such as Processing? As I mentioned before, its likely that you will leverage several tools. A friend of mine who is an artist swears by Processing, Mathematica, and Fortran (Fortran still seems to be the King of scientific computing for some reason) You can use Mathematica for 'Heavy Lifting' and Processing for its Artist friendly focus. Plus, with the cloud, if not already, there shall be some way to integrate the two very tightly.
There is a lot that shows up Mathematica related sites that can be considered Art. Take a look at the HairyStarFish post (just search for it). Merely altering the order of operations a bit to (2/3)^k)^t ends up creating a 'Baboon in a Balloon'. Ink blot tests are always fun.
Good Luck!