Since this is going to be your first AR, I would suggest that you just get a basic rifle and then add stuff as you NEED it. I know that rails and such are all the rage and people like to hang lights, sights and other accessories off of them, but that all adds up in terms of weight. You'd be surprised at the number of 10+ pound carbines I see at the range. If all you are doing is going to the range with it and will be shooting from a bench, then get all of the cool tactical stuff that you need to make you happy.
If you are actually going to be carrying the rifle, I'd consider a few things. The first is that 10lbs feel like a LOT more than 7lbs after you've hiked a few miles with it on your back and I don't care how big you are.
I'd start with something that has plain Jane hand guards (or MOEs) and a simple telescoping stock. Right now, Spike's seems to be the flavor of the month at about $850 for a complete rifle that is built with attention to detail using good milspec parts. In I were in the market for a basic rifle, the price would have to be a lot better than $850 before I'd buy something else. You could, of course spend more for other premium brands and it may well be money well spent.
You could check out aimsurplus.com and order a complete upper and a complete lower and throw them together to save you a little cash. That will leave you with money for a good optics mount and a decent optic.
As far as rails go, I tend to avoid them unless I need them. I've found them to be less comfortable than standard handguards (or MOEs) and they generally add weight/bulk.
I don't have anything against the Stag brand and know a few people that own them, but I wouldn't pay that much money for a Stag rifle, no matter what it had on it. Well, if it had a Nightforce 3.5-15X on it, I'd buy it for the scope and turn around and sell the rifle.
The point is that there are better options for the money. I've seen a good number of Daniel Defense rifles and fit and finish on all of them was top notch. I recently built a rifle around a Daniel Defense upper and was pleasantly surprised by how clean the machine work was, the finish and the tight tolerances.