Quoted:
If this is your first AR, I would suggest shooting it a while with the factory trigger.  The more you shoot them, the better the trigger will get.  Also, if you are going to use this for something other than target shooting or long range work, the regular mil-spec trigger is hard to beat and technique/practice can overcome a heavy trigger.

OTOH, if this isn't your first AR and/or you're going to be shooting a lot of target/long range, then I would suggest a Timney.  I have one and it is fantastic.  The Timneys are single stage and have an excellent break with no creep.  If you are looking 2-Stage, I've heard great things about the Geissele.  The Geisseles are more expensive at around $270+, while the Timneys are around $190+.  Both can be had from Midway, but I would look at the site sponsor sites and see who has them.

Another option that I would consider would be to send your fire control group to Bill Springfield.  His work is from $35 on a trigger group you supply, or you can buy a whole new trigger group with his job from $75.   Everybody raves about his work, and I will be sending a couple of trigger groups his way, but I haven't had any first-hand experience with his work yet.  Once again, I say shoot the standard trigger for a thousand rounds or so and see how things progress.  If you still want a different trigger, then have a gander at Bill Springfield, Timney, and Geissele.  If this is any kind of working gun I suggest sticking with the standard trigger, and at most getting the Springfield trigger job.

Hope this helped a little.
Mike