I think this just shows the problem with a live distro,
You can feed some of the people some of the time but ????

My personal opinion (for what its worth)
Mozilla is too heavy, firebird and thunderbird are better BUT Opera is faster and lighter !!
Konqueror, (what I think you call explorer) is a web browser too and its actually VERY GOOD.

I think kmail rocks as a simple mail client.

Konqueror is very configurable and you can make it behave as you like, one place to look is under the profiles....

klutter on the start menu for me is games!!! but lots will disagree. The problem is that unless you are using a particular item its clutter BUT lots of people might want that item. Take Mozilla - someone might be using knoppix to view web pages actually in Mozilla they are developing.

Fundamentally its really what you make it,
Are you running from Cd only or with a persistant home directory or HDD install ???
(FNAC are doing a great deal on verbatim USB2 64MB dongles at the moment, perhaps that will answer your needs)

Anyway, once you have apersiatant home you can configure it how you like, if your stuck then lots of people here will help

Take the default keyboard for example, thats just the way it is....you can't please everyone so you have to make a choice, if no other reason exists then why not german???

In actual fact the language support is great in knoppix...
Even from a 'English boot' its only two clicks to get a French keyboard!!!