McAfee's ProView was quite nice. You can enter an absolute address to view, or pick a running program, driver, or other memory area. You can scroll through it, search, switch between hex dump and disassembly (probably doesn't support very modern instructions though, it's from 1993), etc. It has a user-friendly Turbo Vision interface.
I think 1.2 was the latest version for DOS (there's a Windows 3.x version which does the same things), PV12.ZIP at http://annex.retroarchive.org/cdrom/smsw-vol3 … TILS/index.html looks like it. That's a site I trust, and if anyone cares, I can try downloading it and comparing against the copy I downloaded in the '90s.