Do you know what sort of game you want?
It's not a matter of genre or game system, it's about the style of game. Increasingly, published games encourage groups intending to play that game to discuss what style of game they are after beforehand, and it's always good practice for a GM to make it clear what sort of game he intends to run - and indeed for players to make any particular opinions known in advance.
Here's an attempt to rate some of the factors that help determine the style of game - from how much GM control there is to how immersive you want play to be, how 'realistic' you expect the action to be and so on. Each factor is given a sliding scale of 1 to 10 - and a silly name, which is only a distraction - and the idea is that the group can come to some concensus about the sort of game they are looking for, thus helping everyone to have some common preconceptions about what will happen when they sit down to play.
The one rating I have issue with is 'Rule Complexity' - that is based on the mechanics of the particular game system you decide to use, rather than on the style of game you want to play. Now that is something you'll have to choose, but in the light of the other areas being considered, you might better look at a scale based on abstraction - do you want to follow the letter of the rules, whatever they may be, all the time or are you comfortable with more abstraction?
It would be an interesting exercise, though, to pass this around your group to see what style would interest them. And it's free... try it out.