I guess it sort of depends on how you define "success"; there's plenty of projects that still have some development and active users.
TeXMacs was release in the late 90's (I think) and it's pretty neat and I think has at least some user base, and I think GNU Parallel was released in the mid 2000s and I know a number of people who use that (including myself).
There are several other important and relatively new GNU projects around - like GNU Radio, Jami, Poke (a semantics-aware binary editor), GNS (DNS alternative), Guile, Mailman, Octave, Parted, R, Shepherd, Taler, GnuCash, DDRescue and numerous others to name. But if you leave out the 'new' part, you'll discover a lot more fantastic gnu projects [1], including Linux's entire coreutils. If you spend enough time with some of them, you'll see how focused, clever, polished and well-integrated many of them are - like bc, units, wget and stow for example. You get the Emacs vibe from many of them. On top of that, a lot of important software are built on top of GNU software like glibc, gsl, gcc, groff, libjit, gmp, ghostscript, libtasn1, readline, aspell, tar (gnu format), termcap, bash, etc. And one thing in common with most of them is their longevity.
Also I can't remember any more recent GNU projects that were successful