I'm doing some Solution4 packaging these days at a client's site. You'll probably ask "what the heck is Solution4"? Take a look at www.loginconsultants.com for more info. In short, it is our own script-based installation and maintenance framework that is primarily used for TS/Citrix environments.
When talking about packaging, we talk about getting applications installed on the Citrix box and making them ready for users to use. And, sadly enough, some applications can really spoil your day (or even days). Take for instance the free Autocad file viewer DWG True View. The installation medium comes with a ready-made MSI, but... you have to tweak the MSI tables to get the thing installed properly. Or, to give another example: the installation gives a strange error if "%ProfileFolder%\Application Data" does not exist.
There are also nice applications, luckily. For people living in Belgium, installing ITT Promedia is very easy: just copy the full contents of the CD and start it. Easy isn't it?!