[Basically the title says it all, until now I've been doing all my coding in XHTML strict....

With html5 being the future however I am rethinking things a little. Should I convert the html over to html 4.01 or html 5. I am honestly loathe to go to html5 yet due to it being new and probably not hugely supported browser marketshare wise.

But I am wondering whether converting the code to html 4.01 might make it easier to up to html 5 when the time comes.
removed What's everyones thoughts on this?

There's really no 'conversion' to do at this point. There's also no reason to delay using HTML5, as long as you're not trying to use the new HTML5-specific tags.

html5 is backwards compatible so your html 4.01 or xhtml 1.1 or whatever should still work. Also as long as you keep the old docytpe that's how browsers will interpret the code. There's really no need to change anything.

On the other hand there's no reason not to start using html5 now as LNR mentioned. You won't be able to use all the specific parts of html5, but a lot has already been adopted by most browsers. There are also some relatively simple workarounds.

I can't claim to have done a lot myself with html5, but I have started using the html5 doctype in all projects and have begun slowly working in some of the new things we can do.

HTML 5 can cope up with the old version also because it is made to accommodate the old code also.