Are the artists on board friends of yours, or are they people you have met online/recruited?
Who is going to be in charge of the design?
If the artists are your friends, then they probably expect some say in what project you go forward with. Even if they're not, you'll want to try and make something that they would be interested in (and therefore more motivated to complete). The most annoying thing that can happen is to start developing a game, and then have the team fall apart because of lack of interest.
You've never programmed AI before, are you therefore expecting to start with something with simple AI to learn? or to jump right in to learning complex AI programming? Get someone else in to help? or to make a game with no AI at all?
If this is your first project (it seems like it is) then you want to aim small. A lot of people jump right in with 'their ultimate team' to create 'the ultimate ultra-super MMO that will revolutionize the industry.' That's just not going to happen if you've never made a game before. A simple puzzle game is your best bet if making something without any AI, or some kind of directly competitive multiplayer game (so you only play versus other people, rather than any AI).
Designing a brand new puzzle game is not easy, and another rehash of a Chain Reaction or Bubble Pop game isn't going to net you much in the way of value or getting on steam - it might be a consideration if you're more interested in the experience at this point, which is a viable route to be taking. A competitive multiplayer game is probably easier to come up with a concept for, but going to be harder to program (in terms of networking and sending/receiving data, although local only multiplayer would be easier).
The questions right now would be, what do you (and your other team members) like to play? What sort of artwork are your artists used to working with? (if they work with 2D sprites, then designing a full 3D modeled game may be out of their league for example). Having possible funding is great. Wasting it is not.
Give some more information on what would you like to build, and maybe we can help brainstorm things through with you.