I don't know if you're trolling or not, but not a single objective person who has a moderate level of football knowledge would argue some of those teams you listed were better than the '91 Eagles D. Do yourself a favor and check those #s again. How many of those teams you listed ranked #1 in run/pass defense? How many held their opponents to less than 4.0 yards a play? The only reason the Eagles D didn't lead the league in points allowed is because their offense was so awful and routinely put the defense in horrible situations. They went through like 4-5 QBs that season. So the defense actually won the Eagles plenty of games that year. That's how good they were.

I'm not choosing the best, but I do believe the '91 Eagles had the most balanced defense of the group. The only defenses I'd consider worthy of contention who were omitted from the original list were the '86 Giants and the 2000 Titans. The '92 NO defense was beastly, but didn't generate as many takeaways as the Eagles D did, plus they got lit up by the Eagles in the playoffs.