A good quality AR15 has suddenly jumped to the very top of the list. A PSA, or maybe even a Colt. Half a dozen magazines to start, and a case or two of ammo to start.
If I end up going to the range more often, maybe a .22 or 9mm upper with a similar supply of magazines and ammo.
A couple of stripped lowers.
And maybe an AK. Depends on the budget after all that.