When I started reloading (which was with 308win for 26 inch barrel) I got some AA2460, some H414, and a brick of magnum primers for them. Seemed like a good idea at the time, and it was all totally new to me.
If I had it to do over again, I would start with Varget, which I got after the AA2460 finished. It seems to do well, and covers a good spread of bullet weights in 308win and 223rem. However does not use the magnum primers.
To finish off the magnum primers, I got some 748 Winchester, which also has a good spread in both 308win and 223rem.
All in all I think I like the Varget best, can't say why. The powder shape (little cylinders) however give me fits with those small 223rem cases.
Have fun. P.S. You might as well get some calipers (a caliper? a set of calipers?). I too started with the RCBS master kit, and they aint in there. You will need a brass tumbler. I tried everything from tying the brass in a sock in the washer to coffee can with cat litter and bon-ami, hand shaken. Finally gave in and got the tumbler from Midway. If you do pistol also you will want the smaller bore cylinder for the powder measure. Ask RCBS nicely and they may send you one free. You will want a chronograph, but that can come later.
Read alot, lurk on the b.boards, and stay safe.