I liked Meet the Parents. Aside from DeNiro's hilarious, "I got nipples Greg, can you milk me?" there's plenty going on in this film to enjoy. I don't like it enough however to talk about it aside from saying, it may have been DeNiro's last decent role in a movie. He hasn't been great since the Cape Fear so that will probably be his last "great" role. The downside of Meet the Parents being his last decent role, it leads to probably his worst decision ever, and that's agreeing to do Little Fockers.
Below, I have prepared a graph mapping DeNiro's decline, a man who was once the greatest actor on earth and his plunge. DeNiro can't undo the great things he did in the 70s and 80s, and will always be much better than Pacino, but he'll probably never be considered to be as good as Brando, and for awhile, he was on that path. Things fall apart though, and Brando himself got weaker as he got older. Hopefully DeNiro will find a new niche. I used to hold my breath for that, but there's barely any chance of it happening. The last time I saw a movie BECAUSE DeNiro was in it in the theatre was The Score but that also had Brando and Ed Norton in it. Naturally, Ed Norton took a Brando/DeNiroesque acting tumble afterwards.
In the graph below, I have not used every DeNiro movie, just some of his more popular ones, and ones that I have seen many many times.