If there's a chance you'll simultaneously use panniers and strap something to the top of the rack, serious consider dual-siderail racks. While you can do both with a regular rack, IME, it involves a lot of cussing and fussing. Dual-siderail racks make it easy peasy instead.
I have a
Tubus Cosmo. The
Topeak Super Tourist DX is another.
This Topeak is perfect but cannot be obtained on this side of the planet.