Judd Vinet: Lately the kernel package has been particularly annoying. There are many different patchsets one can use, and now that the kernel developers have moved to an often-updated 2.6.X.Y versioning scheme, it makes it more difficult for me to distribute up-to-date, stable kernels. Users don't want to download a new kernel each week, reboot, compile custom modules, etc. so I have to try and space these upgrades out as much as I can.
Jan de Groot: I don't have many packages, but from my own packages, the limitation of arch with 1 PKGBUILD -> 1 package really kills gst-plugins because of the splitup (lucky me I know how sed works, updating 45 PKGBUILDs is a breeze then).
Usually I update gnome packages for Arjan and some mozilla-* packages for Dale. The gnome packages are not that bad, but the mozilla-* packages are horrible when it comes to their build system. If I would be openoffice.org maintainer, that package would go straight to number 1 on the most irritating package to create.
Tobias Kieslich: Ask me this now and I will give you a completely different answer than I would in 4 weeks. Currently the mono software is under heavy development. So it is tricky to provide latest software without breaking too many dependencies.
But I also remember blender some times ago when they dropped autotools shortly after they introduced it. scons building support had still some rough edges and the only way to build it were the old NaN shellscripts which are a bit proprietary. On the other hand, blender is a complex piece of software and it builds on many different platforms. So there is need for more complex build systems. It just takes time to get used to it and it's not really documented apart from some comments in the scripts itself.
Damir Perisa: There are no packages that i "must" keep supporting/updating. Almost all the packages i maintain i also use at least weekly. Some of them are essential tools i use daily. There is always one or two packages that are in a state that is not easy to solve (e.g. when the authors change the URL and you need to search for it or when the authors change the building process or the API without announcing it) but this is often solved by the next release of this software. The actual pkg that is in this state is libextractor that wants a static -lgobject-2.0.
Dale Blount: I bet each of us have our own lists for this question, but I'd say that the packages that need patches to build with the latest toolchain are the ones that annoy me personally the most.
Jason Chu: Lots of packages are annoying in their own way, but if I had to pick the worst one it would be gnomemeeting. The intricacies of gconf fail me.
Tobias Powalowski: Well most time consuming is KDE because it's some kind of monster ;) searching new depends, figuring out bug reports, patch security issues, building/testing and give some support in the forum and irc. but i guess it's not different to others DEVS that maintain the big Linux DEs.
Aurelien Foret: I'm not a good candidate to answer this question: I almost only maintain packages for Xfce, and the ones relating to it. No problem here, Xfce folks are doing a great job :)
Arjan Timmerman: The most painfull packages was openoffice for me it doesn't build with the latest gcc, and before that i needed a lot of patching.