Client-side XSL?

What are you smoking?

XSL is fat client technology. 
It will only work on a very small
percentage of immaculately configured
machines.  In other words, almost NONE.
Don't expect the browser vendors
to fix this either.  HTML will be replaced
by full motion video before that happens
(i.e., NEVER).

The last thing I want to see on a website
is "this page best viewed with Opera
and Saxon" or some nonsense like that.  Chances
are your content isn't vital enough to 
justify installing new software.  I'll just
click somewhere else, thank you.  Doubtful I am
unique in that respect.

MAYBE there is a dumbed-down version of
CSS that works on all browsers on all
platforms.  Maybe.  But there
is no version of XSL that even comes close.
The only display technology that has
nearly as much "reach" as HTML 3.0 is Flash.

XSLT is great.  Just don't do it on the client.
Transform your XML on the server.
Otherwise, you and your visitors are in 
for a lot of broken pages.  Don't wait for
IE 10 to have a "compliant" processor,
whatever that is.  Like CSS,
XSLT will forever be a moving target. 

Learn from the problems of Java on the
client and stick with HTML 3 and 
(perhaps) Flash.